A143417 - OEIS

A143417

Irregular triangle in which row n gives the k such that the reduced totient function psi(k) = A002174(n).

1, 2, 3, 4, 6, 8, 12, 24, 5, 10, 15, 16, 20, 30, 40, 48, 60, 80, 120, 240, 7, 9, 14, 18, 21, 28, 36, 42, 56, 63, 72, 84, 126, 168, 252, 504, 32, 96, 160, 480, 11, 22, 33, 44, 66, 88, 132, 264, 13, 26, 35, 39, 45, 52, 65, 70, 78, 90, 91, 104, 105, 112, 117, 130, 140, 144, 156

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Row n consists of the divisors of A143407(n) that are not divisors of A143407(r) for r<n. The length of row n is A143408(n).

LINKS

T. D. Noe, Rows n=1..20, flattened

EXAMPLE

1,2; 3,4,6,8,12,24; 5,10,15,16,20,30,40,48,60,80,120,240

CROSSREFS

Cf. A002322 (reduced totient function).

Sequence in context: A135108 A018515 A018253 * A018597 A018623 A018703

Adjacent sequences: A143414 A143415 A143416 * A143418 A143419 A143420

KEYWORD

nonn,tabf,look

AUTHOR

T. D. Noe, Aug 13 2008

STATUS

approved