

A162887


Odd nonprimes in an alternating 1based sum up to some odd nonprime.


0



15, 33, 39, 51, 69, 75, 87, 105, 117, 123, 129, 141, 159, 177, 183, 189, 195, 201, 213, 219, 231, 243, 249, 255, 267, 279, 285, 303, 309, 315, 321, 327, 333, 339, 357, 369, 375, 381, 393, 399, 411, 429, 435, 447, 453, 459, 465, 483, 489, 495, 501, 513, 519
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OFFSET

1,1


COMMENTS

Define the alternating sum S(u) = sum_{k=0..u} (1(1)^k*k) = A064455(u+1) as in A162886.
Evaluate the sum with upper limits u= 1,9, 15, 21... from A014076, and add S(u) to this sequence here whenever it is itself a member of A014076.


LINKS

Table of n, a(n) for n=1..53.


EXAMPLE

The sequence S(u) = 3, 15, 24, 33, 39, 42, 51, 54, 60, 69, ... is generated by u = 1, 9, 15, 21, ...
The first Sterm, 3, is prime, and therefore not added to the sequence. The second Sterm, 15, is an odd nonprime and added to the sequence. The third, 24, is even and not added to the sequence.


CROSSREFS

Cf. A014076.
Sequence in context: A141230 A140608 A085371 * A231370 A246755 A212311
Adjacent sequences: A162884 A162885 A162886 * A162888 A162889 A162890


KEYWORD

nonn,less


AUTHOR

JuriStepan Gerasimov, Jul 16 2009


EXTENSIONS

3 removed by R. J. Mathar, Aug 27 2009


STATUS

approved



