OFFSET
1,1
COMMENTS
The sum of the reciprocals converges to 0.156047....
It is only a (plausible) conjecture that this sequence is well-defined. See A152052. - N. J. A. Sloane, Aug 22 2014
LINKS
Abhiram R Devesh, Table of n, a(n) for n = 1..100
Eric Weisstein's World of Mathematics, Cousin Primes
PROG
(Python)
import sympy
for i in range(1, 100):
....a=(10**i)
....p=sympy.prevprime(a)
....while sympy.isprime(p-4)==False:
........p=sympy.prevprime(p)
....print(p)
(PARI)
a(n)=p=precprime(10^n); while(!isprime(p-4), p=precprime(p-1)); return(p)
vector(50, n, a(n)) \\ Derek Orr, Aug 04 2014
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Abhiram R Devesh, Aug 02 2014
STATUS
approved