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A229492 Conjectured number of positive even numbers having exactly n representations as the unordered sum of two odd primes. 0
2, 3, 9, 11, 11, 16, 16, 18, 20, 23, 16, 29, 16, 25, 27, 23, 22, 25, 35, 29, 26, 25, 27, 27, 27, 33, 28, 44, 35, 21, 29, 35, 38, 33, 39, 37, 34, 35, 31, 31, 28, 41, 37, 32, 44, 35, 37, 41, 44, 33, 37, 32, 47, 39, 43, 47, 33, 37, 48, 41, 37, 48, 34, 35, 47, 36, 29 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

This sequence is closely related to the Goldbach conjecture, which is equivalent to a(0) = 2; that is, there are no numbers other than 2 and 4 that have no representations as the sum of two odd primes. This is sequence A000974, except for the first two terms.

LINKS

Table of n, a(n) for n=0..66.

EXAMPLE

There are 3 even numbers with one representation: 6 = 3+3, 8 = 3+5, and 12 = 5+7. Hence, a(1) = 3.

CROSSREFS

Cf. A000974 (using both even and odd primes).

Cf. A002375 (number of representations of 2n as the sum of two odd primes).

Sequence in context: A109636 A057236 A063257 * A328970 A103039 A140222

Adjacent sequences:  A229489 A229490 A229491 * A229493 A229494 A229495

KEYWORD

nonn

AUTHOR

T. D. Noe, Oct 31 2013

STATUS

approved

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Last modified July 4 15:43 EDT 2020. Contains 335448 sequences. (Running on oeis4.)