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.

A339737 Triangle read by rows where T(n,k) is the number of integer partitions of n with greatest gap k.

This page as a plain text file.
%I A339737 #17 Jan 14 2024 11:50:22
%S A339737 1,1,0,1,1,0,2,0,1,0,2,1,1,1,0,3,1,1,1,1,0,4,1,2,2,1,1,0,5,1,3,2,2,1,
%T A339737 1,0,6,2,3,4,3,2,1,1,0,8,2,4,5,4,3,2,1,1,0,10,2,5,7,6,5,3,2,1,1,0,12,
%U A339737 3,6,8,9,6,5,3,2,1,1,0,15,3,8,11,11,10,7,5,3,2,1,1,0
%N A339737 Triangle read by rows where T(n,k) is the number of integer partitions of n with greatest gap k.
%C A339737 We define the greatest gap of a partition to be the greatest nonnegative integer less than the greatest part and not in the partition.
%H A339737 Andrew Howroyd, <a href="/A339737/b339737.txt">Table of n, a(n) for n = 0..1325</a> (rows 0..50)
%H A339737 George E. Andrews and David Newman, <a href="https://doi.org/10.1007/s00026-019-00427-w">Partitions and the Minimal Excludant</a>, Annals of Combinatorics, Volume 23, May 2019, Pages 249-254.
%H A339737 Brian Hopkins, James A. Sellers, and Dennis Stanton, <a href="https://arxiv.org/abs/2009.10873">Dyson's Crank and the Mex of Integer Partitions</a>, arXiv:2009.10873 [math.CO], 2020.
%H A339737 Wikipedia, <a href="https://en.wikipedia.org/wiki/Mex_(mathematics)">Mex (mathematics)</a>
%e A339737 Triangle begins:
%e A339737    1
%e A339737    1   0
%e A339737    1   1   0
%e A339737    2   0   1   0
%e A339737    2   1   1   1   0
%e A339737    3   1   1   1   1   0
%e A339737    4   1   2   2   1   1   0
%e A339737    5   1   3   2   2   1   1   0
%e A339737    6   2   3   4   3   2   1   1   0
%e A339737    8   2   4   5   4   3   2   1   1   0
%e A339737   10   2   5   7   6   5   3   2   1   1   0
%e A339737   12   3   6   8   9   6   5   3   2   1   1   0
%e A339737   15   3   8  11  11  10   7   5   3   2   1   1   0
%e A339737   18   4   9  13  15  13  10   7   5   3   2   1   1   0
%e A339737   22   5  10  17  19  18  14  11   7   5   3   2   1   1   0
%e A339737   27   5  13  20  24  23  20  14  11   7   5   3   2   1   1   0
%e A339737 For example, row n = 9 counts the following partitions:
%e A339737   (3321)       (432)   (333)      (54)      (522)    (63)    (72)   (81)  (9)
%e A339737   (22221)      (3222)  (4311)     (441)     (531)    (621)   (711)
%e A339737   (32211)              (33111)    (4221)    (5211)   (6111)
%e A339737   (222111)             (3111111)  (42111)   (51111)
%e A339737   (321111)                        (411111)
%e A339737   (2211111)
%e A339737   (21111111)
%e A339737   (111111111)
%t A339737 maxgap[q_]:=Max@@Complement[Range[0,If[q=={},0,Max[q]]],q];
%t A339737 Table[Length[Select[IntegerPartitions[n],maxgap[#]==k&]],{n,0,15},{k,0,n}]
%o A339737 (PARI)
%o A339737 S(n,k)={if(k>n, O(x*x^n), x^k*(S(n-k,k+1) + 1)/(1 - x^k))}
%o A339737 ColGf(k,n) = {(k==0) + S(n,k+1)/prod(j=1, k-1, 1 - x^j + O(x^max(1,n-k)))}
%o A339737 A(n,m=n)={Mat(vector(m+1, k, Col(ColGf(k-1,n), -(n+1))))}
%o A339737 { my(M=A(10)); for(i=1, #M, print(M[i,1..i])) } \\ _Andrew Howroyd_, Jan 13 2024
%Y A339737 Column k = 0 is A000009.
%Y A339737 Row sums are A000041.
%Y A339737 Central diagonal is A000041.
%Y A339737 Column k = 1 is A087897.
%Y A339737 The version for least gap is A264401, with Heinz number encoding A257993.
%Y A339737 The version for greatest difference is A286469 or A286470.
%Y A339737 An encoding (of greatest gap) using Heinz numbers is A339662.
%Y A339737 A000070 counts partitions with a selected part.
%Y A339737 A006128 counts partitions with a selected position.
%Y A339737 A015723 counts strict partitions with a selected part.
%Y A339737 A048004 counts compositions by greatest part.
%Y A339737 A056239 adds up prime indices, row sums of A112798.
%Y A339737 A064391 is the version for crank.
%Y A339737 A064428 counts partitions of nonnegative crank.
%Y A339737 A073491 list numbers with gap-free prime indices.
%Y A339737 A107428 counts gap-free compositions.
%Y A339737 A238709/A238710 counts partitions by least/greatest difference.
%Y A339737 A342050/A342051 have prime indices with odd/even least gap.
%Y A339737 Cf. A001223, A002110, A018818, A063250, A088860, A098743, A279945.
%K A339737 nonn,tabl
%O A339737 0,7
%A A339737 _Gus Wiseman_, Apr 20 2021
%E A339737 Offset corrected by _Andrew Howroyd_, Jan 13 2024