A264900 Integers k such that A122102(k) + 1 is prime.

1, 13, 43, 71, 101, 149, 163, 191, 233, 257, 259, 277, 307, 311, 373, 389, 421, 439, 463, 563, 571, 617, 647, 743, 751, 763, 871, 899, 907, 971, 1099, 1171, 1223, 1429, 1517, 1577, 1621, 1631, 1687, 1691, 1709, 1741, 1757, 1759, 1777, 1841, 1871, 1963

Offset

1,2

Comments

Only a(11) = 259 is a composite number for n <= 25.

Initial corresponding primes are 17, 6870733, 9723349723 and 190977764951.

Links

Table of n, a(n) for n=1..48.

Example

a(1) = 1 because 2^4 + 1 = 17 is prime.

Mathematica

Select[Range@ 2000, PrimeQ[Sum[Prime[k]^4, {k, #}] + 1] &] (* Michael De Vlieger, Nov 28 2015 *)

Prog

(PARI) a(n) = sum(k=1, n, prime(k)^4)+1;
for(n=0, 3000, if(ispseudoprime(a(n)) , print1(n, ", ")))

Crossrefs

Cf. A122102.

Sequence in context: A043141 A043921 A138686 * A082369 A132233 A282322

Adjacent sequences: A264897 A264898 A264899 * A264901 A264902 A264903

Keyword

nonn

Author

Altug Alkan, Nov 27 2015

Status

approved