# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a375371 Showing 1-1 of 1 %I A375371 #10 Aug 13 2024 11:42:48 %S A375371 1,-1,4,-1,11,7,35,52,138,267,606,1266,2758,5882,12679,27185,58442, %T A375371 125473,269561,578929,1243545,2670942,5736984,12322389,26467324, %U A375371 56849060,122106124,262271540,563332877,1209982051,2598919376,5582216323,11990037159,25753389147 %N A375371 Expansion of 1/( (1 + x)^2 * (1 - x*(1 + x)^2) ). %H A375371 Index entries for linear recurrences with constant coefficients, signature (-1,3,6,4,1). %F A375371 a(n) = -a(n-1) + 3*a(n-2) + 6*a(n-3) + 4*a(n-4) + a(n-5). %F A375371 a(n) = Sum_{k=0..n} binomial(2*k-2,n-k). %o A375371 (PARI) my(N=40, x='x+O('x^N)); Vec(1/((1+x)^2*(1-x*(1+x)^2))) %o A375371 (PARI) a(n) = sum(k=0, n, binomial(2*k-2, n-k)); %Y A375371 Cf. A375373. %K A375371 sign %O A375371 0,3 %A A375371 _Seiichi Manyama_, Aug 13 2024 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE