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

Author

Klaus Brockhaus, Nov 20 2007

Keywords

• nonn

Comments

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

Examples

			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.
		

Links

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

Crossrefs

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