

A078299


Numbers which can be expressed as the sum of two distinct primes in exactly four ways.


4



36, 42, 50, 74, 80, 82, 86, 88, 92, 94, 152, 158
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..12.


EXAMPLE

36 is a term as 36 = 31 + 5 = 29 + 7 = 23 + 13 = 19 + 17 are only the four ways to express 36 as a sum of two distinct primes.


MAPLE

P:=proc(q, w) local a, k, n;
for n from 1 to q do a:=0; for k from 1 to trunc(n/2) do
if isprime(k) and isprime(nk) and n<>2*k then a:=a+1; fi; od;
if a=w then print(n); fi; od; end: P(200, 4); # Paolo P. Lava, May 21 2014


CROSSREFS

Cf. A077914 (2 ways), A077969 (3 ways), A080854 (5 ways), A080862 (6 ways).
Sequence in context: A261372 A044862 A162526 * A225028 A239802 A266242
Adjacent sequences: A078296 A078297 A078298 * A078300 A078301 A078302


KEYWORD

nonn


AUTHOR

Shyam Sunder Gupta, Mar 29 2003


STATUS

approved



