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A168497 The halfs of even single (or even isolated) numbers. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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).

LINKS

Table of n, a(n) for n=1..57.

FORMULA

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

CROSSREFS

Cf. A040040, A167777.

Sequence in context: A308870 A273371 A040040 * A256975 A239882 A086642

Adjacent sequences:  A168494 A168495 A168496 * A168498 A168499 A168500

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Nov 27 2009

EXTENSIONS

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

STATUS

approved

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Last modified June 5 16:19 EDT 2020. Contains 334852 sequences. (Running on oeis4.)