|
|
|
|
1, 2, 3, 4, 5, 6, 7, 12, 45, 64, 121, 144, 238, 261, 415, 2296, 2847
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
Corresponding primes are 5, 11, 41, 227, 2341 and 30071.
1, 4, 64, 121, 144 are squares for initial terms of sequence. Are there any other squares in this sequence?
|
|
LINKS
|
|
|
EXAMPLE
|
a(1) = 1 because 2 + 3 = 5 is prime.
a(2) = 2 because 2*3 + 5 = 11 is prime.
a(3) = 3 because 2*3*5 + 11 = 41 is prime.
|
|
MATHEMATICA
|
Select[Range@ 500, PrimeQ[Product[Prime@ k, {k, #}] + Prime@ Prime@ #] &] (* Michael De Vlieger, Dec 02 2015 *)
|
|
PROG
|
(PARI) lista(nn) = {s = 1; for(k=1, nn, s *= prime(k); if(ispseudoprime(s + prime(prime(k))), print1(k, ", ")); ); }
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|