OFFSET
1,1
COMMENTS
If n is in the sequence and n+1 is prime then n+1 is also in the sequence. Next term is greater than 5450 and the prime corresponding to the next term has more than 18000 digits. Number of digits of primes corresponding to the nine known terms of the sequence are respectively 2,2,3,3,4,5,29,5010 & 5010.
LINKS
Carlos Rivera, Puzzle 8. Primes by Listing, The Prime Puzzles & Problems connection.
EXAMPLE
9 is in the sequence because all nonprime natural numbers up to 9 are 1,4,6,8 & 9 and 98641 is prime.
MATHEMATICA
Do[If[PrimeQ[(v={}; Do[If[ !PrimeQ[n+1-j], v=Join[v, IntegerDigits [n+1-j]]], {j, n}]; FromDigits[v])], Print[n]], {n, 5450}]
CROSSREFS
KEYWORD
base,more,nonn
AUTHOR
Farideh Firoozbakht, Nov 04 2004
STATUS
approved