OFFSET
1,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
FORMULA
EXAMPLE
a(4)=31 because the 4th prime number is 7 and 7-2=5 and 2^5=32 and 32-1=31.
MATHEMATICA
Table[2^(Prime[n]-2)-1, {n, 20}] (* Harvey P. Dale, Feb 25 2011 *)
PROG
(Magma) [2^(NthPrime(n)-2)-1: n in [1..30]]; // Vincenzo Librandi, Sep 06 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, Mar 01 2008
EXTENSIONS
More terms from Harvey P. Dale, Feb 25 2011
STATUS
approved