OFFSET
1,1
COMMENTS
All those terms such that 2n*4^n is equal to p + 4n^2 + 1 belong to A247024.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..500
FORMULA
a(n) << n^5*1024^n by Xylouris' version of Linnik's theorem. - Charles R Greathouse IV, Sep 18 2014
MATHEMATICA
a[n_] := With[{k = n*2^(2*n+1)}, p = -4*n^2-1; While[!PrimeQ[p += k]]; p]; Table[a[n], {n, 1, 23}] (* Jean-François Alcover, Oct 09 2014, translated from Charles R Greathouse IV's PARI code *)
PROG
(PARI) search(u)={ /* Slow, u must be a small integer. */
my(log2=log(2), q, t, t0, L1=List());
forprime(y=3, prime(10^u),
t=log(y+1)\log2;
while(t>t0,
q=4*t^2+y+1;
if(q%(t*(2^(2*t+1)))==0,
listput(L1, [t, y]);
t0=t;
break
,
t--
)));
L1
}
(PARI) a(n)=my(k=n<<(2*n+1), p=-4*n^2-1); while(!isprime(p+=k), ); p \\ Charles R Greathouse IV, Sep 18 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Cano Sep 17 2014
EXTENSIONS
a(10)-a(23) from Charles R Greathouse IV, Sep 18 2014
STATUS
approved