20,2

Coordination sequence for 22-dimensional cyclotomic lattice Z[zeta_23].

Product of 20 consecutive numbers divided by 20!. - Artur Jasinski (grafix(AT)csl.pl), Dec 02 2007

In this sequence there are no primes - Artur Jasinski (grafix(AT)csl.pl), Dec 02 2007

With a different offset, number of n-permutations (n>=20) of 2 objects: u,v, with repetition allowed, containing exactly (20) u's. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 04 2008]

M. Beck and S. Hosten, Cyclotomic polytopes and growth series of cyclotomic lattices, arXiv math.CO/0508136.

Milan Janjic, Two Enumerative Functions

a(n+19)=n(n+1)(n+2)(n+3)(n+4)(n+5)(n+6)(n+7)(n+8)(n+9)(n+10)(n+11)(n+12)(n+13)(n+14)(n+15)(n+16)(n+17)(n+18)(n+19)/20! - Artur Jasinski (grafix(AT)csl.pl), Dec 02 2007, R. J. Mathar, Jul 07 2009

Gf.: x^20/(1-x)^21. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 04 2008, R. J. Mathar, Jul 07 2009]

(Maple) seq(binomial(n, 20), n=20..40); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 04 2008]

Table[n(n+1)(n+2)(n+3)(n+4)(n+5)(n+6)(n+7)(n+8)(n+9)(n+10)(n+11)(n+12)(n+13)(n+1\ 4)(n+15)(n+16)(n+17)(n+18)(n+19)/20!, {n, 1, 100}] - Artur Jasinski (grafix(AT)csl.pl), Dec 02 2007

Pascal's triangle A007318 diagonal [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 04 2008]

Sequence in context: A020267 A064322 A126902 this_sequence A022586 A125409 A161581

Adjacent sequences: A010970 A010971 A010972 this_sequence A010974 A010975 A010976

nonn

N. J. A. Sloane (njas(AT)research.att.com).

Some formulas adjusted to the offset by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 07 2009