A075384 Initial term of n-th group in A075383.

1, 2, 3, 8, 5, 18, 7, 32, 27, 50, 11, 84, 13, 98, 75, 128, 17, 162, 19, 200, 147, 242, 23, 312, 125, 338, 243, 392, 29, 510, 31, 512, 363, 578, 245, 684, 37, 722, 507, 920, 41, 882, 43, 968, 765, 1058, 47, 1392, 343, 1250, 867, 1352, 53, 1458, 605, 1624, 1083, 1682, 59, 2220, 61, 1922, 1449, 2368, 845

Offset

1,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Maple

A075383 := proc(nmax) local a, n, ct, k; a := [1, 2, 4] ; for n from 3 do ct := 0 ; for k from 1 do if (k*n) in a then ; else a := [op(a), k*n] ; ct := ct+1 ; if ct >= n then break ; fi ; fi; od: if nops(a) > nmax then RETURN(a) ; fi; od: end: A075384 := proc(n, a075383) local i, k ; i := 1 ; for k from 1 to n-1 do i := i+k ; if i > nops(a075383) then RETURN(-1) ; fi; od: RETURN(op(i, a075383)) ; end: a075383 := A075383(4000) : for n from 1 to 70 do a084 := A075384(n, a075383) ; if a084 < 0 then break; else printf("%d, ", a084) ; fi; od:

Mathematica

row[n_] := row[n] = If[n == 1, {1}, rows = Join[row /@ Range[n-1]]; ro = {}; For[k = n, Length[ro] < n, k = k + n, If[FreeQ[rows, k], AppendTo[ro, k]]]; ro]; a[n_] := row[n][[1]]; Array[a, 65] (* Jean-François Alcover, Jan 27 2018 *)

Prog

(Haskell)
a075384 = head . a075383_row  -- Reinhard Zumkeller, Nov 29 2015

Crossrefs

Cf. A075383, A075385, A075386, A075387, A075388.

Sequence in context: A050369 A070935 A095164 * A072500 A376014 A208449

Adjacent sequences: A075381 A075382 A075383 * A075385 A075386 A075387

Keyword

nonn

Author

Amarnath Murthy, Sep 22 2002

Extensions

More terms from Reinhard Zumkeller, Jul 09 2004

Removed claim on relation to A096776. Corrected from a(20) on by R. J. Mathar, Oct 31 2008

Status

approved