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Terms are one after the other alternately odd and even.

proposed

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proposed

Paolo P. Lava, <a href="/A228590/b228590.txt">Table of n, a(n) for n = 1..1000</a>

allocated for Paolo P. Lava

Starting from a(1)=1, a(n) is the minimum integer greater than a(n-1) such that a(n)+a(n-1), a(n)*a(n-1)+1 and a(n)*a(n-1)-1 are all primes.

1, 4, 15, 16, 27, 74, 375, 398, 465, 482, 945, 962, 1149, 1228, 1485, 1624, 1737, 1820, 1941, 1990, 2031, 2690, 2787, 3040, 3327, 3436, 3525, 3704, 3855, 3934, 4383, 4484, 4515, 4712, 6375, 6592, 7239, 7322, 7545, 7616, 7935, 8138, 9381, 9518, 11445, 11594

1,2

Terms are one after the other odd and even.

a(4)=16 and 27 is the minimum integer greater than 16 such that 16+27=43, 16*27-1=431, 16*27+1=433 are all primes.

with(numtheory); P:=proc(q) local a, b, n; a:=1; b:=0; print(a);

for n from 1 to q do while not isprime(a+b) and not isprime (a*b+1) and not isprime (a*b-1) do

b:=b+2; od; print(b); a:=b; b:=b+1; od; print(); end: P(10^4);

Cf. A228588, A228589.

allocated

nonn

Paolo P. Lava, Aug 27 2013

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allocated for Paolo P. Lava

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