A144309 a(n) = indices of smallest prime such that gap to next prime not less than 2*n

2, 4, 9, 24, 30, 30, 30, 99, 99, 154, 189, 217, 217, 217, 217, 217, 217, 1183, 1831, 1831, 1831, 1831, 2225, 2225, 2225, 2225, 3385, 3385, 3385, 3385, 3385, 3385, 3385, 3385, 3385, 3385, 14357, 14357, 14357, 14357, 14357, 14357, 14357, 30802, 30802, 30802

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Formula

a(n) = primepi(A100964(n)) = A000720(A100964(n)). - Michel Marcus, Nov 02 2013

Mathematica

a = {}; Do[n = 1; While[(Prime[n + 1] - Prime[n]) < 2 k, n++ ]; AppendTo[a, n], {k, 1, 75}]; a

Crossrefs

For indices of smallest prime such that gap to next prime is exactly equal to 2*n see A000230. For records in this sequence see A005669

Sequence in context: A291981 A326908 A229048 * A080376 A005669 A038664

Adjacent sequences: A144306 A144307 A144308 * A144310 A144311 A144312

Keyword

nonn

Author

Artur Jasinski, Sep 17 2008

Status

approved