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A120280
Row 4 of array in A105272.
3
2, 2, 4, 7, 3, 3, 8, 10, 6, 6, 20, 4, 4, 4, 132, 30, 3, 3, 24, 252, 10, 10, 238, 26, 14, 14, 36, 31, 5, 5, 32, 840, 18, 18, 180, 90, 10, 10, 42, 280, 6, 6, 38, 264, 21, 21, 210, 1540, 26, 26, 52, 10920, 9, 9, 1320, 780, 30, 30, 300, 6, 6, 6, 174, 570, 11, 11, 290, 549, 9, 9
OFFSET
4,1
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: A120280 := proc(n) A105272(n, 4) ; end: for n from 4 to 90 do printf("%d, ", A120280(n)) ; od: # R. J. Mathar, Aug 11 2008
MATHEMATICA
k = 4;
Table[fp = {};
For[col = k, col > 0, col--,
For[row = 0, col + row*k <= n, row++,
AppendTo[fp, col + row*k]]];
LCM @@ Length /@ First[FindPermutation[Range[n], fp]], {n, k,
76}] (* Robert Price, Aug 26 2019 *)
CROSSREFS
Sequence in context: A350764 A249758 A157470 * A212362 A209142 A368518
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(14) by R. J. Mathar, Aug 11 2008
STATUS
approved