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”).
%I #12 Oct 12 2024 16:10:24
%S 1,2,4,7,9,12,18,25,27,31,33,37,39,43,45,49,52,64,76,88,100,112,125,
%T 127,129,134,144,167,169,172,187,189,196,214,226,238,252,284,300,331,
%U 333,339,345,354,374,387,394,407,409,411,417,423,430,447,453,459,467,469
%N a(n) = sum of first n terms of sequence A120877.
%H Michael De Vlieger, <a href="/A120878/b120878.txt">Table of n, a(n) for n = 1..10000</a>
%t nn = 120; c[_] := 0; s = a[1] = c[1] = 1; w = {1}; Do[k = Total@ Map[c, Select[w, Divisible[s, #] &]]; s += k; c[k]++; a[n] = s; If[FreeQ[w, k], AppendTo[w, k]], {n, 2, nn}]; Array[a, nn] (* _Michael De Vlieger_, Oct 12 2024 *)
%o (PARI) {m=60;v=[1];for(n=2,m,a=0;q=sum(i=1,n-1,v[i]);for(j=1,n-1,if(q%v[j]==0,a++));print1(q,",");v=concat(v,a))} \\ Klaus Brockhaus, Aug 16 2006
%Y Cf. A120877.
%K nonn
%O 1,2
%A _Leroy Quet_, Jul 10 2006
%E More terms from _Klaus Brockhaus_, Aug 16 2006