A167777 Even single (or even isolated) numbers.

2, 4, 6, 12, 18, 30, 42, 60, 72, 102, 108, 138, 150, 180, 192, 198, 228, 240, 270, 282, 312, 348, 420, 432, 462, 522, 570, 600, 618, 642, 660, 810, 822, 828, 858, 882, 1020, 1032, 1050, 1062, 1092, 1152, 1230, 1278, 1290, 1302, 1320, 1428, 1452, 1482, 1488

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 11 2009

Keywords

• nonn

Comments

Two together with average of twin prime pairs.

Crossrefs

Cf. A014574 (average of twin prime pairs), A167706 (the single or isolated numbers).

Programs

Maple

Contribution from R. J. Mathar, Apr 14 2010: (Start)
isA007510 := proc(n) if isprime(n) then not isprime(n+2) and not isprime(n-2) ; else false; end if; end proc:
isA014574 := proc(n) if not isprime(n) then isprime(n+1) and isprime(n-1) ; else false; end if; end proc:
A167777 := proc(n) if n = 1 then 2; else for a from procname(n-1)+2 by 2 do if isA007510(a) or isA014574(a) then return(a) ; end if; end do ; end if; end proc:
seq(A167777(n),n=1..60) ; (End)