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 A371994 #15 Apr 22 2024 17:24:51 %S A371994 1,0,1,0,1,5,0,1,19,61,0,1,42,498,1385,0,1,74,1932,19238,50521,0,1, %T A371994 115,5290,114830,1057475,2702765,0,1,165,11805,449539,8949633, %U A371994 79160457,199360981,0,1,224,23016,1360198,47306246,899141244,7768928932,19391512145 %N A371994 Triangle read by rows: Related to the Euler numbers. %C A371994 Inspired by Philippe Deléham's formula for A371637. %F A371994 Triangle T given by [0, 1, 0, 1, 0, 1, 0, 1, ...] DELTA [1, 4, 9, 16, 25, 36, ...] where DELTA is the operator defined by Deléham in A084938. %e A371994 Triangle starts: %e A371994 [0] [1] %e A371994 [1] [0, 1] %e A371994 [2] [0, 1, 5] %e A371994 [3] [0, 1, 19, 61] %e A371994 [4] [0, 1, 42, 498, 1385] %e A371994 [5] [0, 1, 74, 1932, 19238, 50521] %e A371994 [6] [0, 1, 115, 5290, 114830, 1057475, 2702765] %e A371994 [7] [0, 1, 165, 11805, 449539, 8949633, 79160457, 199360981] %o A371994 (SageMath) # Using function GeneralizedDelehamDelta from A372001. %o A371994 def A371994_triangle(dim): %o A371994 a = lambda n: n % 2 %o A371994 b = lambda n: (n + 1)^2 %o A371994 return GeneralizedDelehamDelta([a, b], dim, False) %o A371994 for row in A371994_triangle(8): print(row) %Y A371994 Cf. A000364 (main diagonal), A371637, A371765 (row sums), A372001. %Y A371994 Cf. A084938. %K A371994 nonn,tabl %O A371994 0,6 %A A371994 _Peter Luschny_, Apr 21 2024