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%I #6 Aug 27 2013 09:30:22
%S 1,4,15,16,27,32,57,70,81,92,147,164,183,200,231,232,255,266,327,356,
%T 387,400,423,430,561,562,567,584,645,716,717,764,807,812,855,866,1005,
%U 1006,1083,1138,1203,1208,1233,1298,1359,1372,1395,1396,1455,1498,1551,1568
%N Starting from a(1)=1, a(n) is the minimum integer greater than a(n-1) such that a(n)+a(n-1) and a(n)*a(n-1)-1 are both primes.
%C Terms are alternately odd and even.
%H Paolo P. Lava, <a href="/A228589/b228589.txt">Table of n, a(n) for n = 1..1000</a>
%e a(5)=27 and 27+28=55, 27+29=56, 27+30=57, 27+31=58 are not prime but 27+32=59 is prime and also 27*32-1=863. Thus a(6)=32.
%p with(numtheory); P:=proc(q) local a, b, n; a:=1; b:=0; print(a);
%p for n from 1 to q do while not isprime(a+b) and not isprime (a*b-1) do
%p b:=b+2; od; print(b); a:=b; b:=b+1; od; print(); end: P(10^4);
%Y Cf. A228588, A228590.
%K nonn
%O 1,2
%A _Paolo P. Lava_, Aug 27 2013