A182951
G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(n^2+n).
Original entry on oeis.org
1, 1, 3, 16, 134, 1596, 25193, 501236, 12118038, 346373740, 11460810227, 431732603292, 18269225018646, 858920382899880, 44455946598501069, 2513531512113074244, 154218539815668325502, 10209332972405039928876
Offset: 0
1/(1-x) = 1 + x/(1+x)^2 + 3*x^2/(1+x)^6 + 16*x^3/(1+x)^12 + 134*x^4/(1+x)^20 +...
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{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*(m+1))),n))}
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{a(n)=if(n==0, 1, 1 - sum(j=0, n-1, a(j)*(-1)^(n-j)*binomial(j*(j+1)+n-j-1, n-j)))}
A182956
G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(n*(3*n+1)/2).
Original entry on oeis.org
1, 1, 3, 19, 206, 3324, 72951, 2050623, 70794951, 2911448386, 139376166446, 7628685374172, 470631647696157, 32346417958899335, 2452988261647043436, 203594274671070109776, 18366854200080039470784, 1790264247095540545539321
Offset: 0
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 +...
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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 *)
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{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))}
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{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)))}
Showing 1-2 of 2 results.