A179612 Sums of pairs of betrothed (or quasi-amicable) numbers.

123, 335, 2975, 3223, 4319, 11903, 25479, 30239, 138239, 393119, 416639, 508895, 773759, 861839, 1071359, 1391039, 1645055, 2903039, 2413151, 2298239, 2903039, 2515199, 2557439, 2757887, 2695679, 3856895, 4147199, 4717439, 4245695, 4561919, 5391359, 5322239

Offset: 1

Author

Jonathan Vos Post, Jan 08 2011

Keywords

• nonn

Comments

This is to A161005 sums of pairs of amicable numbers as betrothed (or quasi-amicable) numbers A005276 are to A063990 amicable numbers. The subsequence of primes begins: 11903, 138239, 1071359.

Examples

			a(1) = 48 + 75 = 123 = 3 * 41.
a(2) = 140 + 195 = 335 = 5 * 67.
a(6) = 5775 + 6128 = 11903 is the smallest prime in these pair-sums.
		

Crossrefs

Cf. A000203, A003502, A003503, A005276, A063990, A161005.

Formula

a(n) = A003502(n) + A003503(n). {(j + k) such that sigma(j)=sigma(k)=j+k+1, where sigma=A000203}.

Extensions

More terms from Amiram Eldar, Jan 27 2019