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 A242507 #7 May 20 2014 02:45:17 %S A242507 1,0,9,11,45,121,243,726,1509,3601,8385,17836,40873,87633,188855, %T A242507 409116,859674,1827160,3832786,7981398,16644666,34362355,70866846, %U A242507 145637147,297814569,608309130,1237764177,2512564769,5090761029,10286177231,20750532587,41778968976 %N A242507 Number of compositions of n, where the difference between the number of odd parts and the number of even parts is 9. %C A242507 With offset 18 number of compositions of n, where the difference between the number of odd parts and the number of even parts is -9. %H A242507 Alois P. Heinz, <a href="/A242507/b242507.txt">Table of n, a(n) for n = 9..1000</a> %F A242507 Recurrence (for n>=13): (n-9)*(n+1)*(n+2)*(n+18)*(16*n^4 + 128*n^3 + 344*n^2 + 352*n - 104871)*a(n) = -2592*(n-10)*(n+1)*(n+3)*(n+17)*(2*n+3)*a(n-1) + 2*(n+2)*(16*n^7 + 272*n^6 + 2872*n^5 + 10928*n^4 - 103259*n^3 - 795505*n^2 - 7964385*n - 13572711)*a(n-2) + 2*(n+1)*(n+3)*(2*n+3)*(16*n^5 + 208*n^4 + 1008*n^3 + 3524*n^2 - 96349*n - 123786)*a(n-3) - (n-4)*(n+2)*(n+3)*(n+5)*(16*n^4 + 192*n^3 + 824*n^2 + 1488*n - 104031)*a(n-4). - _Vaclav Kotesovec_, May 20 2014 %Y A242507 Column k=9 of A242498. %K A242507 nonn %O A242507 9,3 %A A242507 _Alois P. Heinz_, May 16 2014