OFFSET
1,1
COMMENTS
The smallest prefixing digits for the Mersenne primes are given in A209385. - Gilbert Mozzo, Mar 07 2012
The next term a(13) has 160 decimal digits. - Andrew Howroyd, Nov 17 2018
LINKS
Henri Lifchitz and Renaud Lifchitz, PRP Top Records
FORMULA
Mersenne prime + n*10^D with D = number of digits of the Mersenne prime.
EXAMPLE
For Mersenne4: -1 + 2^7 + 4*10^3 = 4127 which is prime.
PROG
(PARI)
ppfx(n)={my(w=10^(1+logint(n, 10)), k=n+w); while(!ispseudoprime(k), k+=w); k}
{ for(n=1, 100, my(p=1<<prime(n)-1); if(ispseudoprime(p), print1(ppfx(p), ", "))) } \\ Andrew Howroyd, Nov 17 2018
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Gilbert Mozzo, Dec 12 2011
EXTENSIONS
a(7)-a(9) added by Gilbert Mozzo, Mar 07 2012
a(10)-a(12) from Andrew Howroyd, Nov 17 2018
STATUS
approved