A132835 Largest terms a(n) forming a self-convolution cube of an integer sequence (A132836) such that: a(n) <= 3*a(n-1) for n>0 with a(0)=1.

1, 3, 9, 25, 75, 225, 674, 2022, 6066, 18196, 54588, 163764, 491291, 1473873, 4421619, 13264856, 39794568, 119383704, 358151111, 1074453333, 3223359999, 9670079995, 29010239985, 87030719955, 261092159865, 783276479595

Offset: 0

Author

Paul D. Hanna, Sep 07 2007

Keywords

• nonn

Crossrefs

Cf. A132836 (cube-root); A132831 (variant).

Programs

PARI

{a(n)=local(B=[1],R);if(n==0,1,for(k=1,n,t=3*a(k-1);B=concat(B,t); R=Vec(Ser(B)^(1/3))[ #B]; B[ #B]=t-(numerator(R)%3)*(denominator(R)-1)/2 ));B[n+1]}