A079807 - OEIS

A079807

Number of multiples of 3 that can be formed by permuting the digits of n.

1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 1, 0, 0, 6, 0, 0

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OFFSET

0,13

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

FORMULA

a(3*k+1) = a(3*k+2) = 0, a(3*k) = multinomial(m; c(0),...,c(9)) where c(i) is the number of occurrences of digit i in 3*k and m = c(0)+c(1)+...+c(9). - Sean A. Irvine, Aug 27 2025

EXAMPLE

a(12) = 2: (12,21)

MATHEMATICA

Table[Count[FromDigits/@Permutations[IntegerDigits[n]], _?(Divisible[ #, 3]&)], {n, 0, 110}] (* Harvey P. Dale, Apr 22 2019 *)

CROSSREFS

Cf. A079806.

Sequence in context: A343493 A095808 A281453 * A363887 A341776 A116373

Adjacent sequences: A079804 A079805 A079806 * A079808 A079809 A079810

KEYWORD

base,easy,nonn

AUTHOR

Amarnath Murthy, Feb 06 2003

EXTENSIONS

More terms from Sam Alexander, Feb 26 2005

STATUS

approved