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

0,2

Links

Table of n, a(n) for n=0..25.

Prog

(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]}

Crossrefs

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

Sequence in context: A196431 A244826 A183111 * A191354 A001189 A212352

Adjacent sequences: A132832 A132833 A132834 * A132836 A132837 A132838

Keyword

nonn

Author

Paul D. Hanna, Sep 07 2007

Status

approved