A111014 Primes in the sequence A015519.

2, 11, 149, 2143, 6709949, 446049530175322600739691943

Offset

1,1

Comments

Is there an infinity of primes in this sequence?

References

John Derbyshire, Prime Obsession, Joseph Henry Press, April 2004, p. 16.

Links

Amiram Eldar, Table of n, a(n) for n = 1..9

Formula

Given a(0) = 1, b(0) = 1 then for i = 1, 2, .. a(i)/b(i) = (a(i-1)+2*b(i-1)) /(a(i-1) + b(i-1)).

Mathematica

Select[LinearRecurrence[{2, 7}, {0, 1}, 100], PrimeQ] (* Amiram Eldar, Jun 30 2024 *)

Prog

(PARI) primenum(n, k, typ) = /* k=mult, typ=1 num, 2 denom. output prime num or denom. */ { local(a, b, x, tmp, v); a=1; b=1; for(x=1, n, tmp=b; b=a+b; a=k*tmp+a; if(typ==1, v=a, v=b); if(isprime(v), print1(v", "); ) ); print(); print(a/b+.) }

Crossrefs

Cf. A015519.

Sequence in context: A046912 A185245 A006122 * A171184 A297676 A049462

Adjacent sequences: A111011 A111012 A111013 * A111015 A111016 A111017

Keyword

easy,nonn

Author

Cino Hilliard, Oct 02 2005

Status

approved