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A358992
a(n) is the number of digits in the product of the first n odd numbers not divisible by 5.
3
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
FORMULA
a(n) = A055642(A358990(n)).
MATHEMATICA
Table[Length[IntegerDigits[Product[2i+2Floor[(i-3)/4]+1, {i, n}]]], {n, 0, 65}]
CROSSREFS
Cf. A358991 (number of zero digits), A358993 (number of nonzero digits).
Sequence in context: A165737 A349996 A347517 * A033104 A191325 A190209
KEYWORD
nonn,base
AUTHOR
Stefano Spezia, Dec 09 2022
STATUS
approved