A093306 k-th lower twin prime, where k is the n-th Fibonacci number.

3, 3, 5, 11, 29, 71, 179, 347, 857, 1721, 3359, 6089, 11831, 22271, 41957, 77711, 138401, 249437, 447791, 799739, 1399199, 2459921, 4312739, 7581941, 13233839, 23019041, 39921977, 69112961, 119168381, 205190351, 352286897, 603678287, 1032646421, 1763797499

Offset

1,1

Links

Table of n, a(n) for n=1..34.

Formula

a(n) = A001359(A000045(n)). - R. J. Mathar, Feb 06 2010

Example

For n=6, the 6th Fibonacci number is 8 and the 8th lower twin prime is 71, the 6th entry.

Prog

(PARI) f(n) = for(x=1, n, print1(twinl(fibonacci(x))", ")) twinl(n) = { local(c, x); c=0; x=1; while(c<n, if(isprime(prime(x)+2), c++); x++; ); return(prime(x-1)) }
(PARI) default(primelimit, 20000000); twinl(n) = { local(c, x); c=0; x=1; while(c<n, if(isprime(prime(x)+2), c++); x++); return(prime(x-1)) } { for(n=1, 25, write("b093306.txt", n, " ", twinl(fibonacci(n)))); } \\ Harry J. Smith, Jun 20 2009

Crossrefs

Sequence in context: A201866 A191632 A146918 * A093309 A187874 A126318

Adjacent sequences: A093303 A093304 A093305 * A093307 A093308 A093309

Keyword

nonn

Author

Cino Hilliard, Apr 25 2004

Extensions

a(24)-a(25) from Harry J. Smith, Jun 20 2009

a(26)-a(34) from Giovanni Resta, Jun 10 2018

Status

approved