A340713 - OEIS

A340713

Numbers k such that sigma(k+1) = 4 * sigma(k).

%I #24 Jan 18 2021 03:52:53

%S 37033919,141162839,264995639,596672999,606523679,630777839,791656319,

%T 920424119,1060332839,1379454719,1954690919,3799661039,4024838999,

%U 4633959959,5393988599,5935994063,8831231639,9866482079,11237657759,11273710139,12266364599,14440498379,14952625379

%N Numbers k such that sigma(k+1) = 4 * sigma(k).

%H Seiichi Manyama, <a href="/A340713/b340713.txt">Table of n, a(n) for n = 1..40</a> (using A058072 data)

%o (PARI) isok(k) = sigma(k+1) == 4*sigma(k); \\ _Michel Marcus_, Jan 18 2021

%Y Cf. A000203, A002961, A058072, A067081, A077087, A340715.

%K nonn

%O 1,1

%A _Seiichi Manyama_, Jan 17 2021

%E a(10)-a(23) from _Seiichi Manyama_ using A058072 data, Jan 17 2021