A258573 Number of primes between A002110(n) - A007504(n) and A002110(n) + A007504(n) exclusive where A002110(n) is the primorial numbers and A007504(n) is the sum of first n primes.

0, 2, 4, 4, 4, 6, 5, 6, 14, 9, 9, 17, 14, 18, 16, 11, 23, 19, 23, 27, 25, 23, 28, 16, 33, 26, 25, 36, 36, 31, 40, 35, 37, 35, 39, 39, 33, 46, 51, 46, 48, 43, 46, 44, 44, 64, 66, 63, 53, 68, 60, 68, 53, 63, 52, 52, 62, 64, 68, 66, 66, 75, 80, 61, 84, 90, 88, 74, 70

Offset

1,2

Comments

Number of primes of the form A002110(2n) - A007504(2n) and A002110(2n) + A007504(2n): 0, 1, 2, 2, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...

Links

Table of n, a(n) for n=1..69.

Example

a(1) = 2 because A002110(1) - A007504(1) = 2 - 2 = 0 < (primes 2 and 3) < A002110(1) + A007504(1) = 2 + 2 = 4.

Maple

P:= 1: S:= 0: p:= 0: a[0]:= 0:
for i from 1 to 100 do
  p:= nextprime(p);
  P:= P*p;
  S:= S+p;
  a[i]:= nops(select(isprime, {$(P-S+1)..(P+S-1)}));
od:
seq(a[i], i=0..100); # Robert Israel, Jun 05 2015

Crossrefs

Cf. A002110, A007504.

Sequence in context: A160803 A278481 A084291 * A073806 A060849 A130819

Adjacent sequences: A258570 A258571 A258572 * A258574 A258575 A258576

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jun 03 2015

Extensions

a(13) corrected and a(19) onwards from Robert Israel, Jun 05 2015

Status

approved