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A242291 Greedy-summable tetrahedral numbers. 4
35, 56, 120, 165, 220, 286, 560, 680, 1330, 1540, 1771, 2300, 2600, 2925, 3654, 4495, 4960, 6545, 7140, 7770, 9880, 11480, 12341, 14190, 15180, 16215, 18424, 19600, 20825, 22100, 23426, 27720, 29260, 30856, 35990, 39711, 43680, 45760, 47905, 52394, 54740 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Greedy summability is defined at A242288.

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..1000

EXAMPLE

Let s(n) = n(n+1)(n+2)/6 = A000292(n).  Then

a(1) = 35 = 20 + 10 + 4 + 1;

a(2) = 56 = 35 + 20 + 1;

a(3) = 120 = 84 + 35 + 1;

a(4) = 165 = 120 + 35 + 10.

MATHEMATICA

z = 200;  s = Table[n (n + 1)(n + 2)/6, {n, 1, z}]; t = Table[{s[[n]], #, Total[#] == s[[n]]} &[DeleteCases[-Differences[FoldList[If[#1 - #2 >= 0, #1 - #2, #1] &, s[[n]], Reverse[Select[s, # < s[[n]] &]]]], 0]], {n, z}]

r[n_] := s[[n]] - Total[t[[n]][[2]]];

tr = Table[r[n], {n, 2, z}]  (* A242288 *)

c = Table[Length[t[[n]][[2]]], {n, 2, z}] (* A242289 *)

f = 1 + Flatten[Position[tr, 0]]  (* A242290*)

f (f + 1)(f + 2)/6  (* A242291 *) (* Peter J. C. Moses, May 06 2014 *)

CROSSREFS

Cf. A242288, A242289, A242290, A241833, A242284, A000292.

Sequence in context: A090877 A048033 A254366 * A078819 A189554 A267738

Adjacent sequences:  A242288 A242289 A242290 * A242292 A242293 A242294

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, May 10 2014

STATUS

approved

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Last modified July 21 04:40 EDT 2019. Contains 325189 sequences. (Running on oeis4.)