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A358993
a(n) is the number of nonzero digits in the product of the first n odd numbers not divisible by 5.
3
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
0,4
FORMULA
a(n) = A055640(A358990(n)).
MATHEMATICA
Table[Length[Select[IntegerDigits[Product[2i+2Floor[(i-3)/4]+1, {i, n}]], Positive]], {n, 0, 66}]
CROSSREFS
Cf. A358991 (number of zero digits), A358992 (number of digits).
Sequence in context: A036018 A123552 A071610 * A198726 A117275 A327725
KEYWORD
nonn,base
AUTHOR
Stefano Spezia, Dec 09 2022
STATUS
approved