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 A099526 Expansion of 1/(1-2x-3x^4). 0
 1, 2, 4, 8, 19, 44, 100, 224, 505, 1142, 2584, 5840, 13195, 29816, 67384, 152288, 344161, 777770, 1757692, 3972248, 8976979, 20287268, 45847612, 103611968, 234154873, 529171550, 1195885936, 2702607776, 6107680171, 13802874992 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS In general 1/(1-a*x-b*x^4) expands to sum{k=0..floor(n/4),C(n-3k,k)b^(n-3k)(a/b)^(n-4k)}. LINKS Index entries for linear recurrences with constant coefficients, signature (2,0,0,3). FORMULA a(n)=2a(n-1)+3a(n-4); a(n)=sum{k=0..floor(n/4), binomial(n-3k, k)3^(n-3k)(2/3)^(n-4k)}. CROSSREFS Cf. A099525. Sequence in context: A199694 A037444 A151526 * A005703 A172383 A003081 Adjacent sequences:  A099523 A099524 A099525 * A099527 A099528 A099529 KEYWORD easy,nonn AUTHOR Paul Barry, Oct 20 2004 STATUS approved

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Last modified January 18 07:55 EST 2022. Contains 350454 sequences. (Running on oeis4.)