A286683 - OEIS

A286683

Even numbers k such that the number of odd divisors of k is equal to the 2-adic valuation of k.

2, 12, 20, 28, 44, 52, 68, 72, 76, 92, 116, 124, 148, 164, 172, 188, 200, 212, 236, 240, 244, 268, 284, 292, 316, 332, 336, 356, 388, 392, 404, 412, 428, 432, 436, 452, 508, 524, 528, 548, 556, 560, 596, 604, 624, 628, 652, 668, 692, 716, 724, 764, 772, 788, 796, 816

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

This sequence is infinite; 4 * p is in the sequence for odd prime p. - David A. Corneth, Jun 22 2017

LINKS

Table of n, a(n) for n=1..56.

FORMULA

a(n) = 2*A072978(n).

A001227(a(n)) = A007814(a(n)).

EXAMPLE

2 is in this sequence because A001227(2) = A007814(2) = 1.