A065244 Primes of form p = 2 + Sum_{k = 1..m} k^2 for some m.

3, 7, 821, 1787, 2111, 3313, 3797, 5527, 6203, 13687, 31397, 40427, 63367, 116797, 137827, 208337, 238967, 247067, 281297, 348553, 723907, 811037, 1048063, 1511017, 1538573, 1771177, 2268317, 3064987, 4298387, 4694923, 5239627

Offset

1,1

Links

Table of n, a(n) for n=1..31.

Formula

A000330(m)+2 gives primes.

Example

821 = 2 + (1 + 4 + 9 + 16 + 25 + 36 + 49 + 64 + 81 + 100 + 121 + 144 + 169) = 2 + 919 = c + Sum[k^2;1...13]. Instead of c = 2 several other constants give numerous solutions.

Crossrefs

Cf. A000330, A065245.

Sequence in context: A302987 A092568 A055624 * A012844 A104052 A062625

Adjacent sequences: A065241 A065242 A065243 * A065245 A065246 A065247

Keyword

nonn

Author

Labos Elemer, Oct 24 2001

Status

approved