# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a100135 Showing 1-1 of 1 %I A100135 #24 Dec 24 2023 02:30:02 %S A100135 1,1,1,1,1,1,3,9,21,41,71,113,173,269,443,777,1413,2577,4615,8065, %T A100135 13813,23413,39691,67801,116973,203337,354519,617345,1071197,1851677, %U A100135 3192731,5501033,9485621,16381185,28330119,49035777,84883621,146875717,253983307,438968761 %N A100135 a(n) = Sum_{k=0..floor(n/6)} C(n-3k,3k) * 2^k. %H A100135 Seiichi Manyama, Table of n, a(n) for n = 0..1000 %H A100135 Index entries for linear recurrences with constant coefficients, signature (3,-3,1,0,0,2). %F A100135 G.f.: (1-x)^2/((1-x)^3 - 2*x^6). %F A100135 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + 2*a(n-6). %t A100135 LinearRecurrence[{3,-3, 1, 0, 0, 2},{1,1,1,1,1,1},38] (* _James C. McMahon_, Dec 22 2023 *) %Y A100135 Cf. A098575, A100134, A100136. %K A100135 nonn,easy %O A100135 0,7 %A A100135 _Paul Barry_, Nov 06 2004 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE