A049847 a(n) = (2*n + 1 - prevprime(2*n+1))/2.

1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 3, 1, 1, 2, 3, 1, 2, 1, 1, 2, 1, 2, 3, 1, 2, 3, 1, 1, 2, 3, 1, 2, 1, 1, 2, 3, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 3, 4, 5, 6, 7, 1, 2, 1, 2, 3, 1, 1, 2, 3, 4, 5, 1, 1, 2, 3, 1, 2, 3, 1, 2, 1, 2, 3, 1, 2, 3, 1, 1, 2, 3, 4

Offset

2,4

Links

Table of n, a(n) for n=2..94.

Mathematica

Table[(2n+1-NextPrime[2n+1, -1])/2, {n, 2, 100}] (* Harvey P. Dale, Jul 25 2015 *)

Crossrefs

Cf. A049613, A049653, A049711, A049716.

Sequence in context: A369377 A091304 A340101 * A255274 A025431 A161070

Adjacent sequences: A049844 A049845 A049846 * A049848 A049849 A049850

Keyword

nonn

Author

N. J. A. Sloane

Status

approved