A118960 - OEIS

%I #14 Sep 13 2024 03:32:12

%S 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,

%T 30,90,16,16,84,18,18,60,4,4,1320,42,42,195,11,11,493,42,42,90,6,6,

%U 138,20,20,49,28,28,308,10,10,7800,16,16,1008,22,22,624,12,12,2952,12,12,138

%N Row 3 of array in A105272.

%p 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

%t k = 3;

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

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

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

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

%t LCM @@ Length /@ First[FindPermutation[f, fp]], {n, k, 76}] (* _Robert Price_, Aug 26 2019 *)

%K nonn

%O 3,1

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

%E Extended beyond a(12) by _R. J. Mathar_, Aug 11 2008