A053640 Number of divisors of highly composite odd numbers (A053624).

1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 20, 24, 32, 36, 40, 48, 54, 64, 72, 80, 96, 108, 120, 128, 144, 160, 192, 216, 240, 256, 288, 320, 384, 432, 480, 512, 576, 640, 720, 768, 864, 960, 1024, 1152, 1280, 1440, 1536, 1728, 1920, 2048, 2304, 2560, 2880, 3072, 3456

Offset: 1

Author

Stefano Lanfranco (lastefano(AT)yahoo.it), Mar 22 2000

Keywords

• nonn

Comments

a(n) is the number of divisors of the odd parts of A340506(n); see also comments in A250071. - Hartmut F. W. Hoft, Mar 29 2022

Examples

			a(15) = 6 since A053624(6) = 45 has the 6 divisors 1, 3, 5, 9, 15, 45. - _Hartmut F. W. Hoft_, Mar 29 2022
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..363 (terms 1..170 from Ray Chandler)

Crossrefs

Cf. A000005, A053624.

Cf. A237593, A237048, A237270, A250071, A340506.

Programs

Mathematica

a053640[n_] := Module[{recL={1}, q, d}, For[q=1, q<=n, q+=2, d=Length[Divisors[q]]; If[Last[recL]Hartmut F. W. Hoft, Mar 29 2022 *)

Formula

a(n) = A000005(A053624(n)).

Extensions

Extended by Ray Chandler, Jan 12 2012