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

0,2

Links

Table of n, a(n) for n=0..7.

Example

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.

Sequence in context: A348790 A173876 A368080 * A250549 A035512 A054953

Adjacent sequences: A348788 A348789 A348790 * A348792 A348793 A348794

Keyword

nonn,more,hard

Author

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

Extensions

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

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

Status

approved