Search: id:A151442 Results 1-1 of 1 results found. %I A151442 %S A151442 1,1,2,5,13,37,111,348,1115,3690,12437,42646,148530,523835,1868356,6729649, 24454173,89552497, %T A151442 330263689,1225741014,4575462854,17169395749,64738926261,245187658138, 932406910922, %U A151442 3559219448897,13634163069767,52398809327631,201994189232865,780899820381385, 3027006453635929 %N A151442 Number of walks within N^2 (the first quadrant of Z^2) starting at (0, 0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (0, -1), (0, 1), (1, -1), (1, 0)} %H A151442 M. Bouquet-Melou and M. Mishna, 2008. Walks with small steps in the quarter plane, ArXiv 0810.4387. %t A151442 aux[i_Integer, j_Integer, n_Integer] := Which[Min[i, j, n] < 0 || Max[i, j] > n, 0, n == 0, KroneckerDelta[i, j, n], True, aux[i, j, n] = aux[-1 + i, j, -1 + n] + aux[-1 + i, 1 + j, -1 + n] + aux[i, -1 + j, -1 + n] + aux[i, 1 + j, -1 + n] + aux[1 + i, 1 + j, -1 + n]]; Table[Sum[aux[0, k, n], {k, 0, n}], {n, 0, 25}] %Y A151442 Sequence in context: A114509 A003080 A149854 this_sequence A053732 A119495 A148301 %Y A151442 Adjacent sequences: A151439 A151440 A151441 this_sequence A151443 A151444 A151445 %K A151442 nonn,walk %O A151442 0,3 %A A151442 Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008 Search completed in 0.001 seconds