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A096520 Number of primes in the neighborhood of center=2^n and radius=Ceiling[Log[2^n]]. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
Sequence in context: A335660 A210681 A366544 * A236552 A352628 A080748
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 12 2004
STATUS
approved

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Last modified May 17 19:53 EDT 2024. Contains 372607 sequences. (Running on oeis4.)