

A077914


Sums of two distinct primes in exactly two ways.


8




OFFSET

1,1


COMMENTS

Most likely no more terms. See A117929.  T. D. Noe, Mar 21 2012
Numbers k such that A117929(k) = 2.  Joerg Arndt, Jun 07 2021


LINKS

Table of n, a(n) for n=1..9.
G. L. Honaker, Jr., Prime Curio for 16, April 2000.


EXAMPLE

22 is a term as 22 = 19+3 = 17+5 are the only two ways to express 22 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(100, 2); # Paolo P. Lava, May 21 2014


CROSSREFS

Cf. A077969 (3 ways), A078299 (4 ways), A080854 (5 ways), A080862 (6 ways).
Sequence in context: A043705 A178980 A031315 * A273543 A274127 A328736
Adjacent sequences: A077911 A077912 A077913 * A077915 A077916 A077917


KEYWORD

nonn,more


AUTHOR

Shyam Sunder Gupta, Mar 29 2003


STATUS

approved



