A096520 Number of primes in the neighborhood of center=2^n and radius=Ceiling[Log[2^n]].

2, 3, 3, 3, 2, 3, 2, 2, 1, 3, 1, 3, 1, 1, 2, 3, 2, 5, 1, 4, 1, 2, 4, 2, 0, 2, 0, 2, 2, 5, 3, 3, 2, 0, 0, 3, 2, 2, 3, 2, 2, 3, 1, 4, 0, 2, 2, 1, 0, 2, 1, 2, 1, 1, 2, 2, 4, 1, 0, 1, 4, 0, 2, 2, 0, 3, 3, 2, 2, 2, 1, 1, 1, 3, 1, 3, 3, 3, 2, 1, 2, 4, 1, 3, 1, 3, 1, 1, 5, 3, 2, 1, 2, 2, 4, 2, 0, 4, 0, 1, 1, 2, 0, 2, 2

Offset

1,1

Links

Table of n, a(n) for n=1..105.

Example

First in the suitable neighborhood of 2^25 no primes occur: a[25]=0, while around 2^127 6 primes arise: a[127]=6.

Mathematica

t=Table[Count[Table[PrimeQ[2^n+i], {i, -Ceiling[Log[2^n]//N], Ceiling[Log[2^n]//N]}], True], {n, 1, 256}]

Crossrefs

Cf. A096509-A096523.

Sequence in context: A335660 A210681 A366544 * A236552 A352628 A080748

Adjacent sequences: A096517 A096518 A096519 * A096521 A096522 A096523

Keyword

nonn

Author

Labos Elemer, Jul 12 2004

Status

approved