OFFSET
1,4
COMMENTS
A quadratic tribonacci sequence.
This is to A000283 as a tribonacci (A000213) is to Fibonacci. Two oddities about this sequence: (a) its first 7 terms are identical to terms numbered 2 through 8 of A072878; (b) only one of the first 9 terms are composite. Primes in the sequence begin 3, 11, 131, 17291 and 89398586189293211. What is the next prime?
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..14
MATHEMATICA
Join[{a=1, b=1, c=1}, Table[d=a*a+b*b+c*c; a=b; b=c; c=d, {n, 10}]] (* Vladimir Joseph Stephan Orlovsky, Apr 19 2011 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Jan 02 2006; definition corrected Jan 02 2006
STATUS
approved