A348791 a(n) is the smallest prime that can be written as the sum of a prime number of consecutive primes in exactly n ways, or -1 if no such number exists.

1, 5, 83, 863, 311, 1837067, 254298349, 2372135461

Offset: 0

Author

Harvey P. Dale and N. J. A. Sloane, Nov 30 2021

Keywords

• nonn
• more
• hard

Examples

			a(2) = 83 from 83 = 11+13+17+19+23 (5 primes) = 23+29+31 (3 primes).
a(4) = 311 from
  311 = 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 (11 primes)
  = 31 + 37 + 41 + 43 + 47 + 53 + 59 (7 primes)
  = 53 + 59 + 61 + 67 + 71 (5 primes)
  = 101 + 103 + 107 (3 primes).
		

Crossrefs

Cf. A082283.

See A348790 for a different version.

Extensions

a(6) from Michael S. Branicky, Nov 30 2021

a(7) from Michael S. Branicky, Dec 01 2021