OFFSET
1,4
COMMENTS
Conjecture: a(n) is nonzero for any n > 7.
Clearly this conjecture implies that there are infinitely many primes.
LINKS
Zhi-Wei Sun, Table of n, a(n) for n = 1..250
EXAMPLE
a(1) = 1 since 2*(1 + 1) - 1 = 3 is a prime.
MATHEMATICA
a[n_]:=a[n]=Det[Table[If[PrimeQ[2(i+j)-1], 1, 0], {i, 1, n}, {j, 1, n}]]
Table[a[n], {n, 1, 40}]
CROSSREFS
KEYWORD
sign
AUTHOR
Zhi-Wei Sun, Aug 27 2013
STATUS
approved