A166722 a(n) is the number of divisors of A166721(n).

1, 3, 5, 9, 7, 15, 21, 27, 11, 25, 45, 13, 35, 33, 63, 75, 39, 81, 49, 17, 55, 105, 135, 99, 19, 65, 51, 189, 77, 125, 117, 147, 225, 165, 57, 243, 91, 175, 23, 85, 315, 195, 297, 153, 231, 95, 405, 245, 69, 375, 351, 119, 275, 441, 171, 121, 273, 567, 495, 255, 525

Offset

1,2

Comments

This is a permutation of the odd numbers A005408. - Alois P. Heinz, Mar 04 2018

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..300 from Alois P. Heinz)

Formula

a(n) = A000005(A166721(n)).

Example

a(8) = A000005(A166721(8)) = A000005(900) = A000005(2^2 * 3^2 * 5^2) = (2+1)*(2+1)*(2+1) = 27.

Crossrefs

Cf. A000005, A005408, A048691, A136404, A152674, A166721.

Sequence in context: A348437 A100463 A346969 * A094549 A029642 A221967

Adjacent sequences: A166719 A166720 A166721 * A166723 A166724 A166725

Keyword

easy,nonn

Author

Alexander Isaev (i2357(AT)mail.ru), Oct 20 2009

Extensions

Proper definition (and removal of obscure Comments entries) by Jon E. Schoenfield, Mar 03 2018

Status

approved