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.

A367594 Number of permutations of [n] whose cycle maxima sum to k, where k is chosen so as to maximize this number.

Original entry on oeis.org

1, 1, 1, 2, 7, 27, 142, 834, 5962, 46788, 426708, 4198632, 46516800, 551415936, 7197404976, 99712618560, 1500173940960, 23786129681280, 405087689727360, 7237524061198080, 137652562628778240, 2735042530132523520, 57482464477451489280, 1257272784581092070400
Offset: 0

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Author

Alois P. Heinz, Jan 03 2024

Keywords

Examples

			a(4) = 7 = A143947(4,7): (123)(4), (132)(4), (124)(3), (142)(3), (13)(24),
  (14)(23), (1)(2)(34).
a(5) = 27 = A143947(5,9): (1234)(5), (1243)(5), (1324)(5), (1342)(5), (1423)(5), (1432)(5), (1235)(4), (1253)(4), (1325)(4), (1352)(4), (1523)(4), (1532)(4), (124)(35), (142)(35), (125)(34), (152)(34), (134)(25), (143)(25), (135)(24), (153)(24), (14)(235), (14)(253), (15)(234), (15)(243), (1)(23)(45), (1)(245)(3), (1)(254)(3).
		

Crossrefs

Row maxima of A143947.
Cf. A368678.

Programs

  • Maple
    b:= proc(n) option remember;
          `if`(n=0, 1, expand(b(n-1)*(t-n+x^n)))
        end:
    a:= n-> max(coeffs(subs(t=n, b(n)))):
    seq(a(n), n=0..23);
  • Mathematica
    a[n_] := If[n == 0, 1, Module[{t}, CoefficientList[Product[n-k+t^k, {k, 1, n-1}]*t^(n-1), t] // Max]];
    Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Oct 03 2024 *)

Formula

a(n) = A143947(n,2n-1) for n>=1, a(0) = 1.