A083508 Number of distinct products i*j*k with 1 <= i < j <= k <= n and j < n.

0, 0, 2, 7, 16, 24, 40, 56, 77, 96, 137, 158, 214, 249, 284, 322, 418, 464, 583, 645, 708, 774, 946, 1007, 1125, 1220, 1330, 1420, 1685, 1768, 2069, 2203, 2346, 2492, 2658, 2750, 3166, 3362, 3553, 3675, 4183, 4344, 4909, 5129, 5327, 5575, 6252, 6432, 6849

Offset

1,3

Links

Robert Israel, Table of n, a(n) for n = 1..1000

Maple

V:= Vector(100):
S:= {}:
for n from 1 to 100 do
  S:= S union {seq(i*(n-1)^2, i=1..n-2), seq(seq(i*j*n, i=1..j-1), j=2..n-1)};
  V[n]:= nops(S);
od:
convert(V, list); # Robert Israel, Aug 03 2025

Prog

(PARI) for(n=1, 100, s=Set(); for(i=1, n-2, for(j=i+1, n-1, for(k=j, n, p=i*j*k; if(!setsearch(s, p), s=setunion(s, Set(p)))))); print1(length(s), ", ")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 06 2006

Crossrefs

Cf. A027430, A100435.

Sequence in context: A041341 A296857 A229595 * A048231 A357577 A070169

Adjacent sequences: A083505 A083506 A083507 * A083509 A083510 A083511

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Better definition and more terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 06 2006

Definition corrected by Robert Israel, Aug 03 2025

Status

approved