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A317128 Number of permutations of [n] whose lengths of increasing runs are Fibonacci numbers. 7
1, 1, 2, 6, 23, 112, 652, 4425, 34358, 299971, 2910304, 31059715, 361603228, 4560742758, 61947243329, 901511878198, 13994262184718, 230811430415207, 4030772161073249, 74301962970014978, 1441745847111969415, 29374226224980834077, 626971133730275593916 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..400

MAPLE

g:= n-> (t-> `if`(issqr(t+4) or issqr(t-4), 1, 0))(5*n^2):

b:= proc(u, o, t) option remember; `if`(u+o=0, g(t),

      `if`(g(t)=1, add(b(u-j, o+j-1, 1), j=1..u), 0)+

       add(b(u+j-1, o-j, t+1), j=1..o))

    end:

a:= n-> b(n, 0$2):

seq(a(n), n=0..27);

CROSSREFS

Cf. A000045, A097597, A273001, A317111, A317129, A317130, A317131, A317132, A317444.

Sequence in context: A201693 A063255 A117158 * A185334 A290280 A059513

Adjacent sequences:  A317125 A317126 A317127 * A317129 A317130 A317131

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 21 2018

STATUS

approved

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Last modified November 11 18:50 EST 2019. Contains 329031 sequences. (Running on oeis4.)