A274561 - OEIS

%I #15 Feb 10 2021 01:28:21

%S 10,49,240,550,748,1504,3192,7192,7912,10792,17272,30592,979992,

%T 1713592,4526272,8353792,9928792,11547352,17999992,89283592,173482552,

%U 361702144,1081850752,1845991216,2146926592,11097907192,12985220152,21818579968,34357510144,109170719992,228354264064,279632332792,549746900992,1511712719992,2169800814592

%N Numbers k such that sigma(k) == 0 (mod k+8).

%e sigma(10) mod (10 + 8) = 18 mod 18 = 0.

%p with(numtheory); P:=proc(q,h) local n;  for n from 1 to q do

%p if n+h>0 then if type(sigma(n)/(n+h),integer) then print(n); fi; fi; od; end: P(10^9,8);

%t Select[Range[10^6], Mod[DivisorSigma[1, #], # + 8] == 0 &] (* _Michael De Vlieger_, Jul 05 2016 *)

%Y Cf. A000203, A045770, A067702, A088833, A181598, A274551-A274560, A274562-A274566.

%K nonn

%O 1,1

%A _Paolo P. Lava_, Jul 05 2016

%E a(16)-a(35) from _Giovanni Resta_