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 A291234 #6 Aug 28 2017 09:19:31 %S A291234 1,2,5,12,28,67,156,370,866,2044,4799,11304,26574,62547,147108,346149, %T A291234 814270,1915795,4506952,10603417,24945414,58687660,138068915, %U A291234 324824928,764187814,1797846170,4229645000,9950753025,23410332344,55075627972,129572006209 %N A291234 p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - S - S^2 - S^3 - S^4. %C A291234 Suppose s = (c(0), c(1), c(2), ...) is a sequence and p(S) is a polynomial. Let S(x) = c(0)*x + c(1)*x^2 + c(2)*x^3 + ... and T(x) = (-p(0) + 1/p(S(x)))/x. The p-INVERT of s is the sequence t(s) of coefficients in the Maclaurin series for T(x). Taking p(S) = 1 - S gives the "INVERT" transform of s, so that p-INVERT is a generalization of the "INVERT" transform (e.g., A033453). %C A291234 See A291219 for a guide to related sequences. %H A291234 Clark Kimberling, <a href="/A291234/b291234.txt">Table of n, a(n) for n = 0..1000</a> %H A291234 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1, 5, -2, -7, 2, 5, -1, -1) %F A291234 G.f.: (1 + x - 2 x^2 - x^3 + 2 x^4 + x^5 - x^6)/(1 - x - 5 x^2 + 2 x^3 + 7 x^4 - 2 x^5 - 5 x^6 + x^7 + x^8). %F A291234 a(n) = a(n-1) + 5*a(n-2) - 2*a(n-3) - 7*a(n-4) + 2*a(n-5) + 5*a(n-6) - a(n-7) - a(n-8) for n >= 9. %t A291234 z = 60; s = x/(1 - x^2); p = 1 - s - s^2 - s^3 - s^4; %t A291234 Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A000035 *) %t A291234 Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A291234 *) %Y A291234 Cf. A000035, A291219. %K A291234 nonn,easy %O A291234 0,2 %A A291234 _Clark Kimberling_, Aug 26 2017