A161757 a(n) = (prime(n))^2 - (nonprime(n))^2.

4, 8, 9, 13, 57, 88, 189, 217, 333, 616, 705, 1045, 1281, 1408, 1725, 2233, 2856, 3045, 3760, 4257, 4429, 5217, 5800, 6765, 8184, 8905, 9165, 9928, 10281, 11005, 14193, 15136, 16653, 17017, 19800, 20301, 22048, 23865, 24973, 26904, 28905, 29512, 33117

Offset: 1

Author

Juri-Stepan Gerasimov, Jun 18 2009

Keywords

• nonn

Examples

			a(1)=4-0^2=4. a(2)=9-1^2=8. a(3)=25-4^2=9. a(4)=49-6^2=13. a(5)=121-8^2=57.
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A001248, A141468, A161753.

Programs

Mathematica

A161753:= With[{nn = 2100}, Complement[Range[0, nn], Prime[Range[PrimePi[nn]]]]^2]; Table[Prime[n]^2 - A161753[[n]], {n, 1, 100}] (* G. C. Greubel, Oct 25 2018 *)

Formula

a(n) = A000040(n)^2 - A141468(n)^2 = A001248(n) - A161753(n).

Extensions

Definition condensed, 78 replaced by 88, 145 replaced by 217, 433 replaced by 333 etc. by R. J. Mathar, Jun 27 2009