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A095200

Greatest multiple of n of the form (n-1) + (n-2) + ... + (n-k), or 0 if no such number exists.

0, 0, 3, 0, 10, 12, 21, 0, 36, 30, 55, 60, 78, 70, 105, 0, 136, 108, 171, 180, 210, 176, 253, 240, 300, 234, 351, 168, 406, 420, 465, 0, 528, 408, 595, 252, 666, 532, 741, 480, 820, 840, 903, 880, 990, 782, 1081, 1008, 1176, 900, 1275, 1248, 1378, 1080, 1485, 1512

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OFFSET

1,3

COMMENTS

a(2n-1) = (n-1)*(2n-1) (the (2n-2)-th triangular number, with k = 2n-2). a(2^n) = 0.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(6) = 5 + 4 + 3 = 12.

a(7) = 6 + 5 + 4 + 3 + 2 + 1 = 21.

MAPLE

A095200 := proc(n) local k, m; for k from n to 1 by -1 do m := n*k-k*(k+1)/2 ; if m > 0 and m mod n = 0 then RETURN(m) ; fi ; od ; RETURN(0) ; end: for n from 1 to 100 do printf("%d, ", A095200(n)) ; od ; # R. J. Mathar, Apr 30 2007

MATHEMATICA

Table[Max[Select[Accumulate[Range[n-1, 1, -1]], Divisible[#, n]&]], {n, 60}]/.(-\[Infinity]->0) (* Harvey P. Dale, Jul 24 2018 *)

CROSSREFS

Cf. A095201, A095202.

Sequence in context: A319202 A327072 A327377 * A090460 A071983 A302693

Adjacent sequences: A095197 A095198 A095199 * A095201 A095202 A095203

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jun 05 2004

EXTENSIONS

More terms from R. J. Mathar, Apr 30 2007

STATUS

approved

URL: https://oeis.org/A095200

⇱ A095200 - OEIS