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A077969 Numbers which can be expressed as the sum of two distinct primes in exactly three ways. 4

%I

%S 24,30,34,40,44,46,52,56,58,98,122,128

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

%e 30 is a term as 30 = 23+7 = 19+11 = 17+13 are the only three ways to express 30 as a sum of three distinct primes.

%p P:=proc(q,w) local a,k,n;

%p for n from 1 to q do a:=0; for k from 1 to trunc(n/2) do

%p if isprime(k) and isprime(n-k) and n<>2*k then a:=a+1; fi; od;

%p if a=w then print(n); fi; od; end: P(200,3); # _Paolo P. Lava_, May 21 2014

%Y Cf. A077914 (2 ways), A078299 (4 ways), A080854 (5 ways), A080862 (6 ways).

%K nonn

%O 1,1

%A _Shyam Sunder Gupta_, Mar 29 2003

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Last modified January 26 20:11 EST 2020. Contains 331288 sequences. (Running on oeis4.)