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 A327005 #10 Aug 13 2019 19:33:58 %S A327005 1,1,0,1,0,0,1,0,1,0,1,0,1,0,0,1,0,1,2,4,0,1,0,1,2,3,0,0,1,0,1,2,6,21, %T A327005 31,0,1,0,1,2,6,20,57,0,0,1,0,1,2,6,24,101,231,379,0,1,0,1,2,6,24,100, %U A327005 422,1394,0,0,1,0,1,2,6,24,105,505,2201,5476,6556,0 %N A327005 T(n, k) = Sum_{i=1..n} BM[k][i] where BM is the BellMatrix(x -> x mod n) as defined in A264428. Square array read by ascending antidiagonals for n >= 1 and k >= 1. %C A327005 Rows converge to the main diagonal A327006. %H A327005 Peter Luschny, <a href="https://oeis.org/wiki/User:Peter_Luschny/BellTransform">The Bell transform</a>. %H A327005 J. Riordan, <a href="/A001850/a001850_2.pdf">Letter, Jul 06 1978</a>. %e A327005 [1] 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A327005 [2] 1, 0, 1, 0, 4, 0, 31, 0, 379, 0, 6556, 0, ... %e A327005 [3] 1, 0, 1, 2, 3, 21, 57, 231, 1394, 5476, 32616, 203105, ... %e A327005 [4] 1, 0, 1, 2, 6, 20, 101, 422, 2201, 12560, 76846, 483892, ... %e A327005 [5] 1, 0, 1, 2, 6, 24, 100, 505, 2620, 15383, 97480, 657305, ... %e A327005 [6] 1, 0, 1, 2, 6, 24, 105, 504, 2759, 16186, 103494, 710384, ... %p A327005 # BellMatrix is defined in A264428. %p A327005 T := proc(n, k) BellMatrix(x -> modp(x, n), k): add(i, i in %[k]) end: %p A327005 seq(seq(T(n-k+1,k), k=1..n), n=1..12); %Y A327005 A005046 is a bisection of row 2. Main diagonal is A327006. %Y A327005 Cf. A264428. %K A327005 nonn,tabl %O A327005 1,19 %A A327005 _Peter Luschny_, Aug 13 2019