This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A259709 #17 Jan 05 2025 19:51:40 %S A259709 0,-1,0,4,22,78,240,679,1828,4762,12132,30432,75504,185875,455040, %T A259709 1109540,2697698,6545670,15859128,38384099,92832716,224399570, %U A259709 542226888,1309862496,3163659744,7640066759,18448657344,44545569508,107553559150,259675788510 %N A259709 a(n) = A259708(n,n-1). %H A259709 Eric M. Schmidt, <a href="/A259709/b259709.txt">Table of n, a(n) for n = 1..300</a> %H A259709 L. Carlitz, <a href="/A006502/a006502.pdf">Some polynomials related to Fibonacci and Eulerian numbers</a>, Fib. Quart., 16 (1978), 217. (Annotated scanned copy) %H A259709 L. Carlitz, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/16-3/carlitz1.pdf">Some polynomials related to Fibonacci and Eulerian numbers</a>, Fib. Quart., 16 (1978), 216-226. %F A259709 Empirical: a(n) = 4*a(n-1) - 2*a(n-2) - 6*a(n-3) + 2*a(n-4) + 4*a(n-5) + a(n-6). - _Eric M. Schmidt_, Jul 10 2015 %F A259709 Empirical: G.f.: -x^2*(-1+2*x^2+4*x) / ( (x^2+2*x-1)*(x^2+x-1)^2 ). - _R. J. Mathar_, Jul 15 2015 %Y A259709 Cf. A259708. %K A259709 sign %O A259709 1,4 %A A259709 _N. J. A. Sloane_, Jul 05 2015 %E A259709 More terms from _Eric M. Schmidt_, Jul 10 2015