A114529 Let S(n)=sigma(|n|)/2-n; sequence gives numbers n such that S(S(S(S(n))))=n. May be called {1,2}-sociable number of orders 1 or 2 or 4.

41, 929, 1301, 30240, 32760, 260609, 1441440, 1860768, 2178540, 3205440, 3378240, 3423420, 3914820, 4029480, 4437720, 5738040, 6093360, 6807240, 7136640, 7239120, 7551360, 9402120, 10204740, 12270720, 12405120, 12942720, 13495680, 14627340, 14725620

Offset

1,1

Links

Table of n, a(n) for n=1..29.

Eric Weisstein's World of Mathematics, Sociable Numbers

Crossrefs

Cf. A113285, A114528.

Sequence in context: A182359 A090836 A282928 * A300173 A293619 A177418

Adjacent sequences: A114526 A114527 A114528 * A114530 A114531 A114532

Keyword

nonn

Author

Yasutoshi Kohmoto, Feb 15 2006

Extensions

a(7)-a(29) from Charles R Greathouse IV, Nov 12 2010.

Status

approved