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 A175410 a(n) = (b(m)-1)*b(m) = Sum_{n=b(m)+1,...,c(m)}n, b=A046174, c=A046175, m=n+1. 0

%I #4 Mar 30 2012 18:35:47

%S 132,27060,5269320,1022496552,198362899020,38481433358940,

%T 7465200453136272,1448210416843244880,280945355811546307860,

%U 54501950819034511436292,10573097513564898455783640

%N a(n) = (b(m)-1)*b(m) = Sum_{n=b(m)+1,...,c(m)}n, b=A046174, c=A046175, m=n+1.

%C Solution to (b-1)*b = (c^2+2bc+c)/2.

%e A046174(2) = 12, then 11*12 = 13+14+15+16+17+18+19+20 = 132, is a term. A046174(3) = 165, then 164*165 = 166+167+,....,+285 = 27060, is a term.

%t lst={};k=1;j=0;Do[b=14*k-j-2;AppendTo[lst,(b-1)*b];j=k;k=b,{n,1,16}];lst

%Y A046174, A046175.

%K nonn

%O 1,1

%A _Manuel Valdivia_, May 05 2010

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Last modified August 8 10:51 EDT 2024. Contains 375019 sequences. (Running on oeis4.)