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%I #10 Jan 22 2022 09:39:34
%S 3,12,37,86,185,328,549,834,1225,1776,2427,3278,4303,5464,6827,8470,
%T 10417,12552,15031,17800,20793,24190,27925,32108,36861,42012,47471,
%U 53356,59569,66236,73983,82236,91141,100454,110735,121456,132917
%N a(n) = 1 + Sum(prime(i)*(2*i-1): 1<=i<=n).
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/FigurateNumber.html">Figurate Number</a>.
%t nxt[{n_, a_}] := {n + 1, a + Prime[n + 1] (2 n + 1)}; NestList[nxt,{1,2},50][[All,2]]+1 (* _Harvey P. Dale_, Jul 05 2018 *)
%o (PARI) a(n) = 1 + sum(i=1, n, prime(i)*(2*i-1)); \\ _Michel Marcus_, Jan 22 2022
%Y Cf. A002412.
%Y Equals 1 + A316322(n).
%K nonn
%O 1,1
%A _Reinhard Zumkeller_, Jun 01 2003
%E Definition corrected by _Harvey P. Dale_, Jul 03 2018
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