A232992 Let b(i) = A134204(i) and c(n) = A133242(n); a(n) is the number of primes p <= c(n) such that p is not in {b(0), b(1), ..., b(c(n)-1)}.

1, 1, 2, 1, 1, 2, 2, 3, 2, 1, 2, 3, 6, 7, 6, 7, 7, 7, 6, 5, 7, 12, 11, 10, 10, 9, 10, 12, 11, 12, 11, 10, 9, 9, 8, 8, 8, 9, 8, 8, 8, 7, 10, 16, 16, 16, 19, 18, 17, 16, 15, 15, 16, 16, 17, 16, 15, 16, 16, 19, 19, 20, 20, 19, 18, 17, 16, 17, 20, 19, 20, 19, 18, 18, 19, 23, 24, 23, 25, 24, 25, 27, 26, 27, 27, 26, 25, 25

Offset

1,3

Comments

Computed by David Applegate, Oct 2007.

Arises from studying the question of whether A134204 is an infinite sequence.

Links

David Applegate, Table of n, a(n) for n = 1..10000

David Applegate, C++ Program

David Applegate, Notes on programs and output

David Applegate, The first 106394 lines of output. The first 3 columns give the first 106394 terms of A133242, A133243 and A232992 (the present sequence), and establish that at least 800 million terms of A134204 exist.

Example

Terms b(0) through b(12) of A134202 are (ignore the periods, which are just for alignment):
i:... 0, 1, 2, 3,. 4,. 5,. 6,. 7,. 8,. 9, 10, 11, 12
b(i): 2, 3, 5, 7, 13, 17, 19, 23, 41, 31, 29, 37, 11
c(1) = 12 is the first i for which b(i)<i.
Then a(1) is the number of primes p <= 12 that are not in the set {b(0), ..., b(11)} = {2, 3, 5, 7, 13, 17, 19, 23, 41, 31, 29, 37}.
Only p = 11 is missing, so a(1)=1.

Crossrefs

Cf. A134204, A133242.

Sequence in context: A062083 A133114 A156265 * A165125 A235187 A029333

Adjacent sequences: A232989 A232990 A232991 * A232993 A232994 A232995

Keyword

nonn

Author

N. J. A. Sloane, Dec 13 2013

Status

approved