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A077969 Numbers which can be expressed as the sum of two distinct primes in exactly three ways. 4
24, 30, 34, 40, 44, 46, 52, 56, 58, 98, 122, 128 (list; graph; refs; listen; history; text; internal format)



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


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

if a=w then print(n); fi; od; end: P(200, 3); # Paolo P. Lava, May 21 2014


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

Sequence in context: A080564 A048260 A114635 * A122181 A167758 A248693

Adjacent sequences:  A077966 A077967 A077968 * A077970 A077971 A077972




Shyam Sunder Gupta, Mar 29 2003



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Last modified December 6 04:14 EST 2019. Contains 329784 sequences. (Running on oeis4.)