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 A144257 #11 Dec 11 2019 09:48:49
%S A144257 1,2,0,3,1,0,4,2,1,0,5,3,2,1,0,6,4,3,2,1,0,7,5,4,3,2,1,0,8,6,5,4,3,2,
%T A144257 1,0,9,7,6,5,4,3,2,1,0,10,8,7,6,5,4,3,2,1,0,11,9,8,7,6,5,4,3,2,1,0,12,
%U A144257 10,9,8,7,6,5,4,3,2,1,0,13,11,10,9,8,7,6,5,4,3,2,1,0,14,12,11,10,9,8,7,6,5
%N A144257 Weight array of A086270.
%C A144257 For the definition of weight array, see A144112.
%C A144257 From _Gary W. Adamson_, Feb 18 2010: (Start)
%C A144257 Identical to an infinite lower triangular matrix with (1,2,3,...) in every column but the leftmost column shifted one row upwards, giving:
%C A144257 1;
%C A144257 2, 0;
%C A144257 3, 1, 0;
%C A144257 4, 2, 1, 0;
%C A144257 5, 3, 2, 1, 0;
%C A144257 ...
%C A144257 Let the triangle = M. Row sums = A000124; M * [1,2,3,...] = A050407 starting with offset 3: (1, 2, 5, 11, 21, 36, ...); and lim_{n->inf} M^n = the odd-indexed Fibonacci numbers, A001519: (1, 2, 5, 13, ...). (End)
%F A144257 Row 1 = A000027. All subsequent rows are 0 followed by A000027.
%e A144257 Northwest corner:
%e A144257 1 2 3 4 5 6 7 8 9
%e A144257 0 1 2 3 4 5 6 7 8
%e A144257 0 1 2 3 4 5 6 7 8
%e A144257 0 1 2 3 4 5 6 7 8
%e A144257 0 1 2 3 4 5 6 7 8
%Y A144257 Cf. A086270.
%Y A144257 Cf. A000124, A050407, A001519. - _Gary W. Adamson_, Feb 18 2010
%K A144257 nonn,tabl
%O A144257 1,2
%A A144257 _Clark Kimberling_, Sep 16 2008