A358992 a(n) is the number of digits in the product of the first n odd numbers not divisible by 5.

1, 1, 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 15, 16, 18, 19, 21, 22, 24, 26, 28, 29, 31, 33, 35, 36, 38, 40, 42, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 82, 84, 86, 88, 90, 92, 94, 96, 99, 101, 103, 105, 107, 109, 112, 114, 116

Offset

0,4

Links

Table of n, a(n) for n=0..65.

Formula

a(n) = A055642(A358990(n)).

Mathematica

Table[Length[IntegerDigits[Product[2i+2Floor[(i-3)/4]+1, {i, n}]]], {n, 0, 65}]

Crossrefs

Cf. A045572, A055642, A356860, A358990.

Cf. A358991 (number of zero digits), A358993 (number of nonzero digits).

Sequence in context: A165737 A349996 A347517 * A033104 A191325 A190209

Adjacent sequences: A358989 A358990 A358991 * A358993 A358994 A358995

Keyword

nonn,base

Author

Stefano Spezia, Dec 09 2022

Status

approved