A309956 Product of digits of (n written in base 5).

0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 2, 4, 6, 8, 0, 3, 6, 9, 12, 0, 4, 8, 12, 16, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 0, 2, 4, 6, 8, 0, 3, 6, 9, 12, 0, 4, 8, 12, 16, 0, 0, 0, 0, 0, 0, 2, 4, 6, 8, 0, 4, 8, 12, 16, 0, 6, 12, 18, 24, 0, 8, 16, 24, 32, 0, 0, 0, 0, 0, 0, 3, 6, 9, 12, 0, 6, 12, 18, 24, 0, 9, 18, 27, 36, 0, 12, 24, 36, 48, 0

Offset: 0

Author

Ilya Gutkovskiy, Aug 24 2019

Keywords

• nonn
• base
• look

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A007091, A007954, A053824.

Programs

Magma

[0] cat [&*Intseq(n,5):n in [1..100]]; // Marius A. Burtea, Aug 25 2019

Mathematica

Table[Times @@ IntegerDigits[n, 5], {n, 0, 100}]

PARI

a(n) = my(d = if (n, digits(n,5), [0])); vecprod(d); \\ Michel Marcus, Aug 25 2019

Formula

G.f. A(x) satisfies: A(x) = x * (1 + 2*x + 3*x^2 + 4*x^3) * (1 + A(x^5)).