A160490 The p(n) sequence that is associated with the Lambda triangle A160487

12, 1440, 907200, 101606400, 100590336000, 172613016576000, 31415569016832000, 256351043177349120000, 4471274895099323351040000, 8495422300688714366976000000, 90272357367118278863486976000000

Offset

2,1

Links

Table of n, a(n) for n=2..12.

Maple

nmax:=11; for n from 0 to nmax do cfn2(n, 0) := 1: cfn2(n, n) := (doublefactorial(2*n-1))^2 od: for n from 1 to nmax do for k from 1 to n-1 do cfn2(n, k) := (2*n-1)^2*cfn2(n-1, k-1) + cfn2(n-1, k) od: od: for n from 1 to nmax do Delta(n-1) := sum((1-2^(2*k1-1))* (-1)^(n+1)*(-bernoulli(2*k1)/(2*k1))*(-1)^(k1+n)*cfn2(n-1, n-k1), k1=1..n) /(2*4^(n-1)*(2*n-1)!); LAMBDA(-2, n) := sum(2*(1-2^(2*k1-1))*(-bernoulli(2*k1)/ (2*k1))*(-1)^(k1+n)* cfn2(n-1, n-k1), k1=1..n) / factorial(2*n-2) end do: Lcgz(2) := 1/12: f(2) := 1/12: for n from 3 to nmax do Lcgz(n) := LAMBDA(-2, n-1)/((2*n-2)*(2*n-3)): f(n) := Lcgz(n)-((2*n-3)/(2*n-2))*f(n-1) end do: for n from 1 to nmax do b(n) := denom(Lcgz(n+1)) end do: for n from 1 to nmax do b(n) := 2*n*denom(Delta(n-1))/2^(2*n) end do: p(2) := b(1): for n from 2 to nmax do p(n+1) := lcm(p(n)*(2*n)*(2*n-1), b(n)) end do: seq(p(n), n=2..nmax+1);

Crossrefs

A160487 is the Lambda triangle.

Equals 6*(2*n-2)!*A160476(n).

Sequence in context: A271514 A181856 A161149 * A276905 A015096 A271434

Adjacent sequences: A160487 A160488 A160489 * A160491 A160492 A160493

Keyword

easy,nonn

Author

Johannes W. Meijer, May 24 2009, Sep 18 2012

Status

approved