OFFSET
1,1
LINKS
A. Frank & P. Jacqueroux, International Contest, 2001. Item 13
EXAMPLE
a(1) = 1 + 4 = 5, a(2) = 2 + 3 = 5, a(3) = 5 + 7 = 12, a(4) = 6 + 8 = 14, a(5)= 9 + 10 = 19, a(6) = 11 + 13 = 24, a(7) = 12 + 14 = 26, a(8) = 15 + 16 = 31,...
MATHEMATICA
upto=250; Select[Sort[Join[Total/@Partition[Prime[Range[Ceiling[PrimePi[ upto/2]]]], 2], Total/@Partition[Select[Range[Ceiling[upto/2]], !PrimeQ[#]&], 2]]], #<=upto&] (* Harvey P. Dale, Aug 25 2011 *)
PROG
(PARI) nonprimenum=[]; for(n=1, 200, if(!isprime(n), nonprimenum=concat(nonprimenum, n))); primenum=[]; forprime(n=1, 200, primenum=concat(primenum, n)); nonprimepair=[]; forstep(n=1, length(nonprimenum), 2, nonprimepair=concat(nonprimepair, nonprimenum[n]+nonprimenum[n+1])); primepair=[]; forstep(n=1, length(primenum), 2, primepair=concat(primepair, primenum[n]+primenum[n+1])); vecsort(concat(nonprimepair, primepair))
CROSSREFS
KEYWORD
nonn
AUTHOR
Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 30 2006
STATUS
approved