A182951 -id:A182951

Search: a182951 -id:a182951

Displaying 1-2 of 2 results found.

page 1

A182952

G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(n*(3*n-1)/2).

+10
2

1, 1, 2, 10, 92, 1314, 26216, 682006, 22067246, 858473488, 39151350362, 2052833191416, 121860108702876, 8088426308992214, 594165066779656784, 47891997458689633520, 4205027188507582359156, 399677541092136186656238

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..17.

FORMULA

a(n) = 1 - Sum_{k=0..n-1} a(k)*(-1)^(n-k)*C(k(3k-1)/2 + n-k-1, n-k) for n>0, with a(0)=1.

EXAMPLE

1/(1-x) = 1 + x/(1+x) + 2*x^2/(1+x)^5 + 10*x^3/(1+x)^12 + 92*x^4/(1+x)^22 + 1314*x^5/(1+x)^35 + 26216*x^6/(1+x)^51 +...

PROG

(PARI) {a(n)=if(n==0, 1, polcoeff(-(1-x)*sum(m=0, n-1, a(m)*x^m/(1+x +x*O(x^n))^(m*(3*m-1)/2)), n))}

(PARI) {a(n)=if(n==0, 1, 1 - sum(j=0, n-1, a(j)*(-1)^(n-j)*binomial(j*(3*j-1)/2+n-j-1, n-j)))}

CROSSREFS

Cf. A133316, A182951, A182956, A141761.

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Dec 31 2010

STATUS

approved

A182956

G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(n*(3*n+1)/2).

+10
2

1, 1, 3, 19, 206, 3324, 72951, 2050623, 70794951, 2911448386, 139376166446, 7628685374172, 470631647696157, 32346417958899335, 2452988261647043436, 203594274671070109776, 18366854200080039470784, 1790264247095540545539321

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..335

FORMULA

a(n) = 1 - Sum_{k=0..n-1} a(k)*(-1)^(n-k)*C(k(3k+1)/2 + n-k-1, n-k) for n>0, with a(0)=1.

EXAMPLE

1/(1-x) = 1 + x/(1+x)^2 + 3*x^2/(1+x)^7 + 19*x^3/(1+x)^15 + 206*x^4/(1+x)^26 + 3324*x^5/(1+x)^40 + 72951*x^6/(1+x)^57 +...

MATHEMATICA

nmax=20; b=ConstantArray[0, nmax+1]; b[[1]]=1; Do[b[[n+1]]=1-Sum[b[[j+1]]*(-1)^(n-j)*Binomial[j*(3*j+1)/2+n-j-1, n-j], {j, 0, n-1}]; , {n, 1, nmax}]; b (* Vaclav Kotesovec, Jul 22 2014 *)

PROG

(PARI) {a(n)=if(n==0, 1, polcoeff(-(1-x)*sum(m=0, n-1, a(m)*x^m/(1+x +x*O(x^n))^(m*(3*m+1)/2)), n))}

(PARI) {a(n)=if(n==0, 1, 1 - sum(j=0, n-1, a(j)*(-1)^(n-j)*binomial(j*(3*j+1)/2+n-j-1, n-j)))}