OFFSET
1,1
COMMENTS
Except for the first term 16 = 4^2, a(n) is never a square.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
MAPLE
ZL:=[]:for p from 1 to 1400 do if (isprime(p) and isprime(p+2)) then ZL:=[op(ZL), (((p+2)^2)-p^2)]; fi; od; print(ZL); # Zerinvary Lajos, Mar 08 2007
MATHEMATICA
Select[Table[Prime[n] + 1, {n, 220}], PrimeQ[ # + 1] &] *4 (* Ray Chandler, Oct 12 2005 *)
4+4#&/@Select[Partition[Prime[Range[300]], 2, 1], #[[2]]-#[[1]]==2&] [[All, 1]] (* Harvey P. Dale, Apr 12 2018 *)
PROG
(Haskell)
a111046 = (* 2) . a054735 -- Reinhard Zumkeller, Feb 10 2015
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Oct 06 2005
EXTENSIONS
Edited and extended by Ray Chandler, Oct 12 2005
STATUS
approved