OFFSET
1,1
FORMULA
a(n) = phi(prime(n) + prime(n+1)).
MAPLE
MATHEMATICA
EulerPhi[Total[#]]&/@Partition[Prime[Range[70]], 2, 1] (* Harvey P. Dale, Mar 05 2013 *)
PROG
(PARI) p=2; forprime(q=3, 1e3, print1((p-1)*(q-1)", "); p=q) \\ Charles R Greathouse IV, Feb 21 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Dec 17 2009
EXTENSIONS
Corrected (a(36)=204 removed) by R. J. Mathar, Jan 21 2010
STATUS
approved