OFFSET
0,1
COMMENTS
Primes of type cp#n-1 are in sequence A002313 again, only one such prime was found, cp#1609-1 was certified with Primo. 1609 = 40*40 + 3*3 = 1600 + 9. Because of the starting value 2, cp#n+1 = 3 mod 4 for every possible n, so they are primes, but not primes of sequence A002313. The search limits were 32000 for primes cp#n+1 and 64000 for primes cp#n-1, having more than 10000 decimal digits in the range of 64000.
EXAMPLE
a(0) = 53 with cp#53+1 = 2*5*13*17*29*37*41*53 + 1 = 5152900091
CROSSREFS
KEYWORD
nonn
AUTHOR
Sven Simon, Apr 25 2004
STATUS
approved