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A346388
a(n) is the number of proper divisors of A053742(n) ending with 5.
4
1, 3, 2, 3, 5, 3, 3, 5, 3, 3, 7, 3, 3, 7, 3, 3, 7, 5, 3, 7, 3, 3, 8, 3, 5, 7, 3, 5, 7, 3, 3, 11, 5, 3, 7, 3, 3, 7, 7, 3, 9, 3, 5, 7, 3, 7, 7, 5, 3, 11, 3, 3, 11, 3, 3, 7, 3, 5, 11, 7, 5, 7, 4, 3, 7, 3, 7, 11, 3, 3, 7, 7, 5, 11, 3, 3, 11, 5, 3, 7, 7, 3, 11, 3, 5
OFFSET
0,2
FORMULA
a(n) = A346392(A053742(n)).
EXAMPLE
a(10) = 7 since there are 7 proper divisors of A053742(10) = 525 ending with 5: 5, 15, 25, 35, 75, 105 and 175.
MATHEMATICA
a[n_]:=Length[Drop[Select[Divisors[25+50n], (Mod[#, 10]==5&)], -1]]; Array[a, 90, 0]
CROSSREFS
Cf. A032741, A053742, A346389 (ending with 6), A346392.
Sequence in context: A283893 A112427 A098229 * A128151 A071166 A140358
KEYWORD
nonn,base
AUTHOR
Stefano Spezia, Jul 15 2021
STATUS
approved