OFFSET
1,1
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = A037074(n) + 1. - Jon E. Schoenfield, Jan 13 2015
a(n) = A014574(n)^2. - Jon E. Schoenfield, Jan 14 2015
a(n) = A120875(n) + 2. - Jason Kimberley, Oct 22 2015
MAPLE
P:= select(isprime, {seq(2*i+1, i=1..1000)}):
T:= P intersect map(`+`, P, 2):
sort(convert(map(t -> (t-1)^2, T), list)); # Robert Israel, Nov 18 2015
MATHEMATICA
f[n_]:=Prime[n]*Prime[n+1]+1; lst={}; Do[If[IntegerQ[Sqrt[f[n]]], AppendTo[lst, f[n]]], {n, 4*5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Feb 10 2010 *)
PROG
(Haskell)
a075369 = (^ 2) . a014574 -- Reinhard Zumkeller, Feb 10 2015
(PARI) p=2; forprime(b=3, 1e3, if(b-p==2, print1(b*p+1", ")); p=b) \\ Altug Alkan, Nov 10 2015
(Magma) [a: n in [1..300] | IsSquare(a) where a is NthPrime(n)*NthPrime(n+1)+1]; // Vincenzo Librandi, Nov 19 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 20 2002
STATUS
approved