OFFSET
0,2
FORMULA
EXAMPLE
For n = 39: 2^39 = 549755813888, prime(549755813889) = 16149760533343, prime(549755813888) = 16149760533341, difference = 2 (just twin primes), so a(39) = 2.
MATHEMATICA
Table[Prime[1+2^n] - Prime[2^n], {n, 1, 39}]
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Labos Elemer, Aug 21 2002
EXTENSIONS
More terms from Michel ten Voorde Jun 13 2003
a(42) from Max Alekseyev, May 08 2009
Offset corrected by Max Alekseyev, Oct 24 2013
a(43)-a(57) from Chai Wah Wu, Aug 30 2019
STATUS
approved