login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Numbers k such that Sum_{i=1..k} i^7 divides Product_{i=1..k} i^7.
5

%I #6 Nov 16 2014 16:13:29

%S 1,733,1637,2096,2367,4231,5674,5839,7585,8344,13719,13753,14983,

%T 15151,15197,15257,15757,16595,17305,18791,20701,21442,23652,23738,

%U 24519,24789,25474,25916,25933,27474,27487,29185,31455,32846,32950,33421

%N Numbers k such that Sum_{i=1..k} i^7 divides Product_{i=1..k} i^7.

%e a(2) = A125314(7) = 733.

%t With[{c=Range[40000]^7},Flatten[Position[#[[1]]/#[[2]]&/@Thread[ {Rest[ FoldList[ Times,1,c]],Accumulate[c]}],_?IntegerQ]]] (* _Harvey P. Dale_, Nov 16 2014 *)

%Y Cf. A123314, A166602, A060462, A166604, A166605, A166606, A166608, A166609, A166610.

%K nonn

%O 1,2

%A _Alexander Adamchuk_, Oct 18 2009

%E More terms from _Max Alekseyev_, Sep 30 2010