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A118960
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Row 3 of array in A105272.
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3
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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
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3,1
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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: 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
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MATHEMATICA
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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 *)
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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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