A063932 Average of largest prime less than or equal to n and smallest prime greater than or equal to n.

2, 3, 4, 5, 6, 7, 9, 9, 9, 11, 12, 13, 15, 15, 15, 17, 18, 19, 21, 21, 21, 23, 26, 26, 26, 26, 26, 29, 30, 31, 34, 34, 34, 34, 34, 37, 39, 39, 39, 41, 42, 43, 45, 45, 45, 47, 50, 50, 50, 50, 50, 53, 56, 56, 56, 56, 56, 59, 60, 61, 64, 64, 64, 64, 64, 67, 69, 69, 69, 71, 72, 73

Offset

2,1

Links

Harry J. Smith, Table of n, a(n) for n = 2..1000

Formula

a(n) = (A007917(n) + A007918(n))/2 = n - A063933(n).

Example

a(7) = (7 + 7)/2 = 7;
a(8) = (7 + 11)/2 = 9.

Mathematica

Table[Mean[{NextPrime[n-1], NextPrime[n+1, -1]}], {n, 2, 80}] (* Harvey P. Dale, Nov 22 2011 *)

Prog

(PARI) { for (n=2, 1000, write("b063932.txt", n, " ", (precprime(n) + nextprime(n))/2) ) } \\ Harry J. Smith, Sep 02 2009

Crossrefs

Interleaving of A000040 and A001223-1 copies of A024675. Cf. A063934.

Sequence in context: A187098 A187099 A284049 * A323785 A327626 A179464

Adjacent sequences: A063929 A063930 A063931 * A063933 A063934 A063935

Keyword

nonn

Author

Henry Bottomley, Aug 21 2001

Status

approved