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 A063897 a(n) is the least k such that k - A000215(j), j=0..n, are all primes. 1
 5, 8, 22, 274, 65704, 4295145556, 18446744073810262144 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Is this sequence finite? The prime k-tuples conjecture implies that the sequence is infinite. - Robert Israel, Jul 11 2016 LINKS EXAMPLE For j=0 a(0)=5 because 5-3 is prime. For j=1 a(1)=8 because 8-5, 8-3 are all primes. For j=2 a(2)=22 because 22-17, 22-5, 22-3 are all primes. For j=3 a(3)=274 because 274-257, 274-17, 274-5, 274-3 are all primes. MAPLE f:= proc(n) local r, j, good; for r from 2^(2^n)+4 by 2 do good:= true; for j from 0 to n do if not isprime(r - 2^(2^j)-1) then good:= false; break fi od; if good then return(r) fi od end proc: f(0):= 5: map(f, [\$0..5]); # Robert Israel, Jul 11 2016 PROG (PARI) okprime(mink, vecf) = {for (i = 1, #vecf, if (! isprime(mink - vecf[i]), return (0)); ); return (1); } a(n) = {mink = 2^(2^n) + 2; vecf = vector(n+1, i, 2^(2^(i-1)) + 1); while (! okprime(mink, vecf), mink++); mink; } \\ Michel Marcus, Sep 28 2013 CROSSREFS Cf. A000215. Sequence in context: A120041 A120042 A120043 * A092733 A116884 A192651 Adjacent sequences: A063894 A063895 A063896 * A063898 A063899 A063900 KEYWORD hard,more,nonn AUTHOR Felice Russo, Aug 29 2001 EXTENSIONS 18446744073810262144 from Thomas Baruchel, Oct 21 2003 STATUS approved

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Last modified December 10 02:09 EST 2022. Contains 358712 sequences. (Running on oeis4.)