A121253 a(n) = a(n-1)*a(n-3)+1 with a(0)=a(1)=a(2)=0.

0, 0, 0, 1, 1, 1, 2, 3, 4, 9, 28, 113, 1018, 28505, 3221066, 3279045189, 93469183112446, 301070407771273987437, 987223472152664180906141290594, 92274971491542102812339702600558728264132925

Offset: 0

Author

Jonathan Vos Post, Aug 22 2006

Keywords

• nonn
• easy

Comments

Analog of A007660 a(n)=a(n-1)*a(n-2)+1. What is the equivalent continued fraction and asymptotic representation?

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..26 (shortened by _N. J. A. Sloane_, Jan 13 2019)

Crossrefs

Cf. A007660.

Programs

Magma

I:=[0,0,0]; [n le 3 select I[n] else Self(n-1)*Self(n-3)+1: n in [1..20]]; // Vincenzo Librandi, Nov 14 2011

Mathematica

RecurrenceTable[{a[0]==a[1]==a[2]==0,a[n]==a[n-1]a[n-3]+1},a,{n,20}] (* Harvey P. Dale, Dec 30 2011 *)

Extensions

More terms from Vincenzo Librandi, Nov 14 2011