A135146 Index of first occurrence of n in A069360.

1, 2, 4, 6, 9, 12, 15, 24, 21, 33, 65, 36, 30, 42, 45, 148, 63, 72, 60, 84, 81, 75, 90, 129, 114, 132, 144, 126, 159, 120, 105, 156, 150, 168, 198, 189, 219, 222, 430, 180, 318, 165, 252, 291, 195, 240, 321, 231, 225, 294, 610, 210, 372, 417, 270, 414, 790, 357

Offset

0,2

Comments

a(n) = smallest k > 0 such that there are n prime pairs (p,q), p < q, with (p+q)/2 = 2*k.

Links

Klaus Brockhaus, Table of n, a(n) for n = 0..1000

Example

Number of prime pairs (p,q) with (p+q)/2 = 2*1 is 0, hence a(0) = 1.
9 is the smallest k such that there are four prime pairs (p,q) with (p+q)/2 = 2*k: (5+31)/2 = (7+29)/2 = (13+23)/2 = (17+19)/2 = 18 = 2*9. Hence a(4) = 9.

Crossrefs

Cf. A069360, A134677 (records in A069360), A134678 (where records occur in A069360).

Sequence in context: A036441 A180107 A375983 * A256956 A257637 A258027

Adjacent sequences: A135143 A135144 A135145 * A135147 A135148 A135149

Keyword

nonn

Author

Klaus Brockhaus, Nov 20 2007

Status

approved