A346388 a(n) is the number of proper divisors of A053742(n) ending with 5.

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

Links

Table of n, a(n) for n=0..84.

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

Adjacent sequences: A346385 A346386 A346387 * A346389 A346390 A346391

Keyword

nonn,base

Author

Stefano Spezia, Jul 15 2021

Status

approved