A358993 a(n) is the number of nonzero digits in the product of the first n odd numbers not divisible by 5.

1, 1, 1, 2, 3, 3, 4, 6, 7, 9, 10, 12, 12, 13, 15, 18, 17, 20, 21, 22, 24, 25, 27, 29, 31, 32, 34, 34, 35, 40, 40, 45, 45, 45, 46, 47, 46, 52, 55, 55, 59, 58, 60, 59, 66, 66, 65, 69, 70, 74, 80, 79, 84, 75, 83, 90, 89, 87, 92, 95, 91, 95, 104, 98, 102, 110, 107

Offset: 0

Author

Stefano Spezia, Dec 09 2022

Keywords

• nonn
• base

Crossrefs

Cf. A045572, A055640, A356861, A358990.

Cf. A358991 (number of zero digits), A358992 (number of digits).

Programs

Mathematica

Table[Length[Select[IntegerDigits[Product[2i+2Floor[(i-3)/4]+1, {i, n}]], Positive]], {n, 0, 66}]

Formula

a(n) = A055640(A358990(n)).