

A285525


The indices that mark the beginning of four consecutive equal terms in A285524.


2



13, 38, 63, 85, 110, 135, 160, 185, 210, 232, 257, 282, 307, 332, 354, 379, 404, 429, 454, 479, 501, 526, 551, 576, 601, 626, 648, 673, 698, 723, 748, 770, 795, 820, 845, 870, 895, 917, 942, 967, 992
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..41.
Robert Davis, Sarah A. Nelson, T. Kyle Petersen, Bridget E. Tenner, The pinnacle set of a permutation, arXiv:1704.05494 [math.CO], 2017.


MATHEMATICA

b[n_] := b[n] = MaximalBy[Table[{d, d! (d+1)! 2^(n  2d  1) StirlingS2[n  d, d + 1]}, {d, 1, n/2}], Last][[All, 1]] // Min;
A285524 = Table[b[n], {n, 4, 1000}];
Position[If[Length[#] == 4, Join[{0}, Rest[#]], #]& /@ Split[A285524] // Flatten, 0] + 3 // Flatten (* JeanFrançois Alcover, Feb 23 2019 *)


PROG

(PARI) half(n) = if (n % 2, n\2, n/2  1);
a285524(n) = {v = vector(half(n), d, d!*(d + 1)!*(2^(n2*d1)*stirling(nd, d+1, 2))); w = vecsort(v, , 1); w[#w]; }
lista(nn) = {v = vector(nn, n, a285524(n+3)); for (k=1, #v4, if ((v[k] == v[k+1]) && (v[k] == v[k+2]) && (v[k] == v[k+3]), print1(k+3, ", ")); ); }


CROSSREFS

Cf. A285524, A285526.
Sequence in context: A244185 A044090 A044471 * A209991 A299055 A158647
Adjacent sequences: A285522 A285523 A285524 * A285526 A285527 A285528


KEYWORD

nonn,more


AUTHOR

Michel Marcus, Apr 20 2017


STATUS

approved



