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A203693 Vandermonde sequence using x^2 - xy + y^2 applied to the first n triangular numbers: 1,3,6,10,...,n(n+1)/2. 3
1, 7, 5859, 3201146676, 3820181459144204700, 25381616622722369500521817413900, 2012800150183968180465350145758736863679028900800, 3623820214658807704726540455788270697258988626189027049678195383091200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A093883 for a discussion and guide to related sequences.

LINKS

Table of n, a(n) for n=1..8.

MATHEMATICA

f[j_] := j (j + 1)/2; z = 11;

u[n_] := Product[f[j]^2 - f[j] f[k] + f[k]^2,

  {j, 1, k - 1}]

v[n_] := Product[u[n], {k, 2, n}]

Table[v[n], {n, 1, z}]          (* A203693 *)

Table[v[n + 1]/v[n], {n, 1, z}] (* A203694 *)

CROSSREFS

Sequence in context: A246519 A062644 A103174 * A125036 A098803 A246853

Adjacent sequences:  A203690 A203691 A203692 * A203694 A203695 A203696

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jan 04 2012

STATUS

approved

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Last modified June 3 23:57 EDT 2020. Contains 334808 sequences. (Running on oeis4.)