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 A260672 #23 Feb 16 2025 08:33:26 %S A260672 0,1,0,2,1,0,3,2,1,4,3,2,5,4,3,0,6,5,4,1,7,6,5,2,0,8,7,6,3,1,9,8,7,4, %T A260672 2,10,9,8,5,3,11,10,9,6,4,12,11,10,7,5,0,13,12,11,8,6,1,14,13,12,9,7, %U A260672 2,15,14,13,10,8,3,0,16,15,14,11,9,4,1,17,16 %N A260672 Table read by rows: T(n,k) = n - A001318(k), k = 0 .. A193832(n)-1. %C A260672 Column k starts at row A001318(k); each column = A001477. %H A260672 Reinhard Zumkeller, <a href="/A260672/b260672.txt">Rows n = 0..1000 of triangle, flattened</a> %H A260672 Sylvie Corteel, Carla D. Savage, Herbert S. Wilf, Doron Zeilberger, <a href="https://doi.org/10.1006/jcta.1997.2846">A pentagonal number sieve</a>, J. Combin. Theory Ser. A 82 (1998), no. 2, 186-192. %H A260672 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PentagonalNumberTheorem.html">Pentagonal Number Theorem</a> %H A260672 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentagonal_number_theorem">Pentagonal number theorem</a> %F A260672 Number of m-tuples of partitions of n that have no part in common = Sum(A087960(k)*A000041(T(n,k))^m: k = 0 .. A193832(n+1)-1), e.g. A054440 (m=2) and A260664 (m=3); see Wilf link: p. 2, (3). %e A260672 . 0: 0 %e A260672 . 1: 1 0 %e A260672 . 2: 2 1 0 %e A260672 . 3: 3 2 1 %e A260672 . 4: 4 3 2 %e A260672 . 5: 5 4 3 0 %e A260672 . 6: 6 5 4 1 %e A260672 . 7: 7 6 5 2 0 %e A260672 . 8: 8 7 6 3 1 %e A260672 . 9: 9 8 7 4 2 %e A260672 . 10: 10 9 8 5 3 %e A260672 . 11: 11 10 9 6 4 %e A260672 . 12: 12 11 10 7 5 0 %e A260672 . 13: 13 12 11 8 6 1 %e A260672 . 14: 14 13 12 9 7 2 %e A260672 . 15: 15 14 13 10 8 3 0 %e A260672 . 16: 16 15 14 11 9 4 1 %e A260672 . 17: 17 16 15 12 10 5 2 %e A260672 . 18: 18 17 16 13 11 6 3 %e A260672 . 19: 19 18 17 14 12 7 4 %e A260672 . 20: 20 19 18 15 13 8 5 . %o A260672 (Haskell) %o A260672 a260672 n k = a260672_tabf !! n !! k %o A260672 a260672_row n = a260672_tabf !! n %o A260672 a260672_tabf = map (takeWhile (>= 0) . flip map a001318_list . (-)) [0..] %Y A260672 Cf. A001318, A193832 (row lengths), A000041, A087960, A054440, A260664, A260706 (row sums). %K A260672 nonn,tabf,look %O A260672 0,4 %A A260672 _Reinhard Zumkeller_, Nov 15 2015