A074705 a(1)=4; for n>1: number of primes between squares of (n-1)-th and (n+1)-th primes.

4, 7, 11, 21, 24, 31, 33, 38, 74, 63, 73, 101, 64, 66, 126, 158, 110, 122, 156, 96, 136, 181, 189, 277, 252, 131, 129, 129, 142, 454, 453, 264, 214, 348, 357, 240, 368, 314, 326, 393, 271, 432, 433, 221, 219, 538, 942, 647, 250, 248, 436, 360, 528, 713, 549

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

Primes between A000040(3-1)^2=3*3=9 and A000040(3+1)^2=7*7=49: {11,13,17,19,23,29,31,37,41,43,47}, therefore a(3)=11.

Mathematica

Join[{4}, Last[#]-First[#]&/@Partition[PrimePi[Prime[Range[60]]^2], 3, 1]] (* Harvey P. Dale, Jun 13 2016 *)

Crossrefs

Sequence in context: A002974 A130625 A104102 * A352216 A288111 A352214

Adjacent sequences: A074702 A074703 A074704 * A074706 A074707 A074708

Keyword

nonn

Author

Reinhard Zumkeller, Sep 03 2002

Status

approved