A132833 Largest terms a(n) forming a self-convolution of an integer sequence (A132834) such that: a(n) <= 3*a(n-1) for n>0 with a(0)=1.

1, 2, 5, 14, 42, 126, 377, 1130, 3390, 10170, 30509, 91526, 274577, 823730, 2471190, 7413570, 22240710, 66722130, 200166390, 600499170, 1801497510, 5404492530, 16213477590, 48640432770, 145921298310, 437763894930, 1313291684789

Offset: 0

Author

Paul D. Hanna, Sep 07 2007

Keywords

• nonn

Crossrefs

Cf. A132834 (square-root); A132831 (variant).

Programs

PARI

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