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Excedance set of A122111. Numbers k < A122111(k), where A122111 represents partition conjugation using Heinz numbers.
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%I #18 Mar 25 2022 21:23:34

%S 3,5,7,10,11,13,14,15,17,19,21,22,23,25,26,28,29,31,33,34,35,37,38,39,

%T 41,42,43,44,45,46,47,49,51,52,53,55,57,58,59,61,62,63,65,66,67,68,69,

%U 70,71,73,74,76,77,78,79,82,83,85,86,87,88,89,91,92,93,94

%N Excedance set of A122111. Numbers k < A122111(k), where A122111 represents partition conjugation using Heinz numbers.

%C The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). The sequence lists all Heinz numbers of partitions whose Heinz number is less than that of their conjugate.

%H Alois P. Heinz, <a href="/A352487/b352487.txt">Table of n, a(n) for n = 1..10000</a>

%H Richard Ehrenborg and Einar Steingrímsson, <a href="https://www.ms.uky.edu/~jrge/Papers/Excedance.pdf">The Excedance Set of a Permutation</a>, Advances in Applied Mathematics 24, (2000), 284-299.

%H MathOverflow, <a href="https://mathoverflow.net/questions/359684/why-excedances-of-permutations">Why 'excedances' of permutations? [closed]</a>.

%F a(n) < A122111(a(n)).

%e The terms together with their prime indices begin:

%e 3: (2)

%e 5: (3)

%e 7: (4)

%e 10: (3,1)

%e 11: (5)

%e 13: (6)

%e 14: (4,1)

%e 15: (3,2)

%e 17: (7)

%e 19: (8)

%e 21: (4,2)

%e 22: (5,1)

%e 23: (9)

%e 25: (3,3)

%e 26: (6,1)

%e 28: (4,1,1)

%e For example, the partition (4,1,1) has Heinz number 28 and its conjugate (3,1,1,1) has Heinz number 40, and 28 < 40, so 28 is in the sequence, and 40 is not.

%t primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];

%t conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];

%t Select[Range[100],#<Times@@Prime/@conj[primeMS[#]]&]

%Y These partitions are counted by A000701.

%Y The weak version is A352489, counted by A046682.

%Y The opposite version is A352490, weak A352488.

%Y These are the positions of negative terms in A352491.

%Y A000041 counts integer partitions, strict A000009.

%Y A000700 counts self-conjugate partitions, ranked by A088902 (cf. A258116).

%Y A003963 = product of prime indices, conjugate A329382.

%Y A008292 is the triangle of Eulerian numbers (version without zeros).

%Y A008480 counts permutations of prime indices, conjugate A321648.

%Y A056239 adds up prime indices, row sums of A112798 and A296150.

%Y A122111 = partition conjugation using Heinz numbers, parts A321649/A321650.

%Y A124010 gives prime signature, sorted A118914, length A001221, sum A001222.

%Y A173018 counts permutations by excedances, weak A123125.

%Y A238744 = partition conjugate of prime signature, ranked by A238745.

%Y A330644 counts non-self-conjugate partitions, ranked by A352486.

%Y A352521 counts compositions by subdiagonals, rank statistic A352514.

%Y Cf. A000720, A114088, A120383, A175508, A290822, A304360, A316524, A319005, A325040.

%K nonn

%O 1,1

%A _Gus Wiseman_, Mar 19 2022