##How it works

How it works

><> and Whitespace exit with an error after giving the correct output, which is allowable by default.

><> and Whitespace exit with an error after giving the correct output, which is allowed by default.

7 Languages, 193 bytes

2/3#^4 9 if 1: x="+++++++[>+++++++<-]>."#3 R = input() try: print(int(eval(chr(49)+chr(47)+chr(40)+chr(49)+chr(47)+chr(50)+chr(41))*int(R))) except: print(7**int(R)) n=2 R 

• In Jelly, produces A000027.

• In Python2, produces A000420.

• In Python3, produces A005843.

• In Brainfuck, produces A000012.

• In ///, produces A007395.

• In Ohm, produces A010734.

• In ><>, produces A010709.

><> exits with an error after giving the correct output, which is allowable by default.

2/3#^4 9 -- the IP travels right (pushing 2) until it hits `/` f -- it travels up (pushing f=15) until it hits `/` -- it travels right (pushing 3) until it hits `#` -- it travels left (pushing 3) until it hits `/` -- it travels down (pushing f=15) until it hits `/` -- it travels left (pushing 2 then 9 then 4) until it hits `^` -- it travels up. When it hits `n`, it prints the 4 -- it then hits some characters ><> doesn't like, -- ending the program with an error. n 

9 Languages, 217 bytes

2/3#^4 9  5 if 1: x="+++++++[>+++++++<-]>."#3 R = input() try: print(int(eval(chr(49)+chr(47)+chr(40)+chr(49)+chr(47)+chr(50)+chr(41))*int(R))) except: print(7**int(R)) R="6"#N; n=2 R 

• In Jelly, produces A000027.

• In Python2, produces A000420.

• In Python3, produces A005843.

• In Brainfuck, produces A000012.

• In ///, produces A007395.

• In Ohm, produces A010734.

• In ><>, produces A010709.

• In Fission 2, produces A010722

• In Whitespace, produces A0000004

><> and Whitespace exit with an error after giving the correct output, which is allowable by default.

2/3#^4 9 -- the IP travels right (pushing 2) until it hits `/` f -- it travels up (pushing f=15) until it hits `/` -- it travels right (pushing 3) until it hits `#` -- it travels left (pushing 3) until it hits `/` -- it travels down (pushing f=15) until it hits `/` -- it travels left (pushing 2 then 9 then 4) until it hits `^` -- it travels up. When it hits `n`, it prints the 4 -- it then hits some characters ><> doesn't like, -- ending the program with an error. n  

Fission

Fission sees:

R="6"#N; R - start an IP/atom going right " - start string 6 - 6 " - end string N - add newline ; - end program. (implicit) print 

(it sees other lines, but those don't affect output) Whitespace

Some of this has likely been lost in copy-paste.

Whitespace sees the following, where N represents linefeed, S represents space, and T represents tab. All actual newlines should be ignored.

NSSN SSSN -- push 0 TN -- print it NTNSNSSNSSSSNSSNSSSSNSSNSSSSNSSSSNSSSSNSSN