cp's OEIS Frontend

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.

A353315 Triangle read by rows where T(n,k) is the number of integer partitions of n with k parts on or below the diagonal (weak non-excedances).

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%I A353315 #8 May 16 2022 05:10:44
%S A353315 1,0,1,1,0,1,1,1,0,1,1,2,1,0,1,1,2,2,1,0,1,2,2,3,2,1,0,1,2,3,3,3,2,1,
%T A353315 0,1,3,4,4,4,3,2,1,0,1,3,6,5,5,4,3,2,1,0,1,4,7,8,6,6,4,3,2,1,0,1,4,9,
%U A353315 10,9,7,6,4,3,2,1,0,1,6,10,14,12,10,8,6,4,3,2,1,0,1
%N A353315 Triangle read by rows where T(n,k) is the number of integer partitions of n with k parts on or below the diagonal (weak non-excedances).
%H A353315 MathOverflow, <a href="https://mathoverflow.net/questions/359684/why-excedances-of-permutations">Why 'excedances' of permutations? [closed]</a>.
%e A353315 Triangle begins:
%e A353315   1
%e A353315   0  1
%e A353315   1  0  1
%e A353315   1  1  0  1
%e A353315   1  2  1  0  1
%e A353315   1  2  2  1  0  1
%e A353315   2  2  3  2  1  0  1
%e A353315   2  3  3  3  2  1  0  1
%e A353315   3  4  4  4  3  2  1  0  1
%e A353315   3  6  5  5  4  3  2  1  0  1
%e A353315   4  7  8  6  6  4  3  2  1  0  1
%e A353315   4  9 10  9  7  6  4  3  2  1  0  1
%e A353315   6 10 14 12 10  8  6  4  3  2  1  0  1
%e A353315   6 13 16 17 13 11  8  6  4  3  2  1  0  1
%e A353315   8 15 21 21 19 14 12  8  6  4  3  2  1  0  1
%e A353315   9 19 24 28 24 20 15 12  8  6  4  3  2  1  0  1
%e A353315 For example, row n = 9 counts the following partitions (empty column indicated by dot):
%e A353315   9   72   522   3222   22221  222111  2211111  21111111  .  111111111
%e A353315   54  81   621   4221   32211  321111  3111111
%e A353315   63  333  711   5211   42111  411111
%e A353315       432  3321  6111   51111
%e A353315       441  4311  33111
%e A353315       531
%t A353315 pgeq[y_]:=Length[Select[Range[Length[y]],#>=y[[#]]&]];
%t A353315 Table[Length[Select[IntegerPartitions[n],pgeq[#]==k&]],{n,0,15},{k,0,n}]
%Y A353315 Row sums are A000041.
%Y A353315 Column k = 0 is A003106.
%Y A353315 The strong version is A114088.
%Y A353315 The opposite version is A115720/A115994, rank statistic A257990.
%Y A353315 The version for permutations is A123125, strong A173018.
%Y A353315 The version for compositions is A352522, rank statistic A352515.
%Y A353315 The strong opposite version is A353318.
%Y A353315 A000700 counts self-conjugate partitions, ranked by A088902.
%Y A353315 A001522 counts partitions with a fixed point, ranked by A352827 (unproved).
%Y A353315 A008292 is the triangle of Eulerian numbers.
%Y A353315 A064428 counts partitions w/o a fixed point, ranked by A352826 (unproved).
%Y A353315 A238352 counts reversed partitions by fixed points, rank statistic A352822.
%Y A353315 A352490 gives the nonexcedance set of A122111, counted by A000701.
%Y A353315 Cf. A002620, A006918, A008290, A008930, A098825, A219282, A238874, A300788, A353319.
%K A353315 nonn,tabl
%O A353315 0,12
%A A353315 _Gus Wiseman_, May 15 2022