A175906 Numbers n of the form 2^(A000043-1)*A046528 such that sigma(n) is a perfect number.

12, 10924032, 16125952, 3757637632, 45091651584, 66563866624, 727145809044307968, 1152771972099211264, 845044701535107443245558061611352064

Offset: 1

Author

Manuel Valdivia, Oct 12 2010

Keywords

• nonn

Comments

sigma(sigma(A046528(2,12,13,18,21,22,56,57,175,176,177,..))) is Mersenne prime.

Examples

			45091651584=2^18*3*7*8191, sigma(45091651584)=137438691328 is perfect number.
		

Crossrefs

Cf. A000396, A000203, A000668, A000043, A046528, A063103.

Formula

a(n)= 2^( A000043(2,5,5,6,7,7,8,8,9,9,9,..)-1)*A046528(2,12,13,18,21,22,56,57,175,176,177,..).