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Improved version of A002685; main diagonal of A324124.
6

%I #14 Oct 30 2019 03:44:23

%S 1,2,6,34,250,972,15498,109544,5961306,54891535,2488870076,

%T 246264587430,118503860254,16917328320424,31020551370600,

%U 459016311081816,25084010473396186126,22789919291848918932,3423598216929042597,82480361346228654485320,12440086312584102532500,121292379506812780007192

%N Improved version of A002685; main diagonal of A324124.

%C Sequence A002685 has only 10 terms (from n = 1 to n = 10). We have a(n) = A002685(n) for 1 <= n <= 10 except for n = 7: a(7) = 109544 while A002685(7) = 766808 (which is a(7) * 7 = 109544 * 7). For an explanation, see the comments for array A324124. This is necessary to give a unique definition to the terms of array A324124.

%H Petros Hadjicostas, <a href="/A328884/a328884.txt">Maple program</a>.

%H Yudell L. Luke, <a href="https://doi.org/10.1090/S0025-5718-1952-0050993-8">Mechanical quadrature near a singularity</a>, Math. Comp. 6 (1952), 215-219.

%Y Cf. A002685, A002686, A324124, A328866, A328885.

%K nonn

%O 0,2

%A _Petros Hadjicostas_, Oct 29 2019