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A120280
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Row 4 of array in A105272.
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3
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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
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listen;
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OFFSET
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4,1
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LINKS
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MAPLE
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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
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MATHEMATICA
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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,
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Aug 10 2008, based on email from Samuel Minter (abulsme(AT)abulsme.com0, May 08 2008, Aug 10 2008
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EXTENSIONS
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STATUS
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approved
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