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 A144870 #10 Sep 16 2019 19:26:31 %S A144870 1,1,1,1,4,1,2,1,1,5,9,1,9,3,1,2,9,1,9,6,2,12,9,1,8,13,1,4,9,6,9,2,8, %T A144870 16,9,1,9,13,9,7,9,3,9,18,1,13,9,2,4,12,8,14,9,1,37,4,8,13,9,8,9,16,1, %U A144870 2,38,11,9,20,7,16,9,1,9,12,13,14,21,16,9,12,1,13,9,6,37,12,16,20,9,8,22,17 %N A144870 Shadow transform of C(n+8,9) = A000582(n+8). %H A144870 Alois P. Heinz, <a href="/A144870/b144870.txt">Table of n, a(n) for n = 1..1000</a> %H A144870 Lorenz Halbeisen and Norbert Hungerbuehler, <a href="https://www.semanticscholar.org/paper/Number-theoretic-aspects-of-a-combinatorial-Halbeisen-Hungerb%C3%BChler/5743ff2f9c14d22d1a9e570d6951a7c9ef79a612">Number theoretic aspects of a combinatorial function</a>, Notes on Number Theory and Discrete Mathematics 5(4) (1999), 138-150; see Definition 7 for the shadow transform. %H A144870 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>. %p A144870 shadow:= proc(p) proc(n) local j; add (`if` (modp(p(j), n)=0, 1,0), j=0..n-1) end end: f:= proc(k) proc(n) binomial (n+k-1,k) end end: a:= n-> shadow (f(9))(n): seq (a(n), n=1..100); %Y A144870 9th column of A144871. Cf. A007318. %K A144870 nonn %O A144870 1,5 %A A144870 _Alois P. Heinz_, Sep 23 2008