A118960 - OEIS

A118960

Row 3 of array in A105272.

2, 2, 4, 6, 6, 4, 4, 4, 21, 3, 3, 30, 4, 4, 90, 18, 18, 24, 5, 5, 48, 20, 20, 6, 6, 6, 28, 30, 30, 90, 16, 16, 84, 18, 18, 60, 4, 4, 1320, 42, 42, 195, 11, 11, 493, 42, 42, 90, 6, 6, 138, 20, 20, 49, 28, 28, 308, 10, 10, 7800, 16, 16, 1008, 22, 22, 624, 12, 12, 2952, 12, 12, 138

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OFFSET

3,1

LINKS

Table of n, a(n) for n=3..74.

MAPLE

abulsme := proc(L, k) local r, p, dangl, R, c; R := ceil(nops(L)/k) ; p := [] ; dangl := nops(L) mod k ; for c from k to 1 by -1 do for r from 1 to R do if r = R and dangl>0 and c>dangl then break; fi; p := [op(p), op(c+k*(r-1), L) ] ; od: od: RETURN(p) ; end: isSrtd := proc(L) for i from 1 to nops(L)-1 do if op(i, L) > op(i+1, L) then RETURN(false) ; fi; od: RETURN(true) ; end: A105272 := proc(n, k) local a, L; L := [seq(i, i=1..n)] ; a := 1 ; L := abulsme(L, k) ; while not isSrtd(L) do L := abulsme(L, k) ; a := a+1 ; od: RETURN(a) ; end: A118960 := proc(n) A105272(n, 3) ; end: for n from 3 to 80 do printf("%d, ", A118960(n)) ; od: # R. J. Mathar, Aug 11 2008

MATHEMATICA

k = 3;

Table[f = Range[n]; fp = {};

For[col = k, col > 0, col--,

For[row = 0, col + row*k <= n, row++,

AppendTo[fp, f[[col + row*k]]]]];

LCM @@ Length /@ First[FindPermutation[f, fp]], {n, k, 76}] (* Robert Price, Aug 26 2019 *)

CROSSREFS

Sequence in context: A303306 A347797 A351746 * A107797 A316788 A038759

Adjacent sequences: A118957 A118958 A118959 * A118961 A118962 A118963

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 10 2008, based on email from Samuel Minter (abulsme(AT)abulsme.com), May 08 2008, Aug 10 2008

EXTENSIONS

Extended beyond a(12) by R. J. Mathar, Aug 11 2008

STATUS

approved