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 A121869 Monthly Problem 10791, first expression. 1

%I

%S -1,1,0,-5,-15,104,1827,7893,-207000,-5646249,-47897675,1479282600,

%T 74711288407,1396956334921,-21032523700672,-2719998717430365,

%U -104158663871982343,-715846242343471272,189941380201812700699,14820744271258596866013,507768838531742620183176

%N Monthly Problem 10791, first expression.

%H A. Fekete and G. Martin, <a href="https://www.jstor.org/stable/2695545">Problem 10791: Squared Series Yielding Integers</a>, Amer. Math. Monthly, 108 (No. 2, 2001), 177-178.

%F a(n) = A024429(n)^2 - A024430(n)^2.

%Y Cf. A121870, A024429, A024430, A121867, A121868.

%K sign

%O 0,4

%A _N. J. A. Sloane_, Sep 05 2006

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Last modified May 22 21:03 EDT 2019. Contains 323499 sequences. (Running on oeis4.)