A189994 Length of the longest run of consecutive primes < 10^n that are not Ramanujan primes.

3, 4, 7, 13, 20, 36, 47, 47, 65

Offset

1,1

Links

Table of n, a(n) for n=1..9.

J. Sondow, Ramanujan primes and Bertrand's postulate Amer. Math. Monthly 116 (2009), 630-635.

J. Sondow, J. W. Nicholson, and T. D. Noe, Ramanujan Primes: Bounds, Runs, Twins, and Gaps, J. Integer Seq. 14 (2011) Article 11.6.2.

Example

Of the 4 primes < 10^1, the last 3 are not Ramanujan primes, so a(1) = 3.

Crossrefs

Cf. A104272 (Ramanujan primes), A189993 (length of the longest run of Ramanujan primes < 10^n), A174641 (smallest prime that begins a run of n non-Ramanujan primes).

Sequence in context: A193883 A227038 A358914 * A125118 A310008 A299024

Adjacent sequences: A189991 A189992 A189993 * A189995 A189996 A189997

Keyword

nonn

Author

Jonathan Sondow, May 03 2011

Status

approved