A115402 Difference between 3-almostprime(n) and 3-almostprime(n+3).

12, 15, 10, 10, 15, 16, 15, 8, 8, 18, 16, 16, 7, 9, 8, 8, 17, 22, 21, 10, 7, 11, 12, 11, 7, 10, 9, 13, 14, 22, 18, 15, 7, 16, 12, 16, 7, 7, 4, 4, 10, 12, 13, 8, 9, 19, 22, 27, 23, 19, 14, 8, 11, 8

Offset: 1

Author

Jonathan Vos Post, Jan 22 2006

Keywords

• easy
• nonn

Examples

			a(1) = A014612(1+3) - A014612(1) = 20 - 8 = 12.
a(2) = A014612(2+3) - A014612(2) = 27 - 12 = 15.
a(3) = A014612(3+3) - A014612(3) = 28 - 18 = 10.
a(39) = A014612(39+3) - A014612(39) = 174 - 170 = 4.
		

Links

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

Crossrefs

Cf. A014612, A056809, A067813, A113789, A115403.

Programs

Mathematica

Last[#]-First[#]&/@Partition[Select[Range[300],PrimeOmega[#]==3&],4,1] (* Harvey P. Dale, Nov 09 2012 *)

Formula

a(n) = A014612(n+3) - A014612(n).