A168497 The halfs of even single (or even isolated) numbers.

1, 2, 3, 6, 9, 15, 21, 30, 36, 51, 54, 69, 75, 90, 96, 99, 114, 120, 135, 141, 156, 174, 210, 216, 231, 261, 285, 300, 309, 321, 330, 405, 411, 414, 429, 441, 510, 516, 525, 531, 546, 576, 615, 639, 645, 651, 660, 714, 726, 741, 744, 804, 810, 834, 849, 861, 894

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 27 2009

Keywords

• nonn

Comments

Essentially the same as A040040: 1, followed by A040040. - Joerg Arndt, Jun 18 2015

Even single (or isolated) numbers/2. Unit together with (average of twin prime pairs (A014574), divided by 2).

Crossrefs

Cf. A040040, A167777.

Formula

a(n)=A167777(n)/2.

Extensions

Entries checked by R. J. Mathar, Apr 14 2010