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A280729
(p-1)/2 + phi(p-1) as p runs through the odd primes.
1
2, 4, 5, 9, 10, 16, 15, 21, 26, 23, 30, 36, 33, 45, 50, 57, 46, 53, 59, 60, 63, 81, 84, 80, 90, 83, 105, 90, 104, 99, 113, 132, 113, 146, 115, 126, 135, 165, 170, 177, 138, 167, 160, 182, 159, 153, 183, 225, 186, 228, 215, 184, 225, 256, 261, 266, 207, 226, 236, 233
OFFSET
1,1
LINKS
FORMULA
a(n) = A098006(n)+2*A008330(n). - R. J. Mathar, Jan 10 2017
MAPLE
A280729 := proc(n)
local p;
p := ithprime(n+1) ;
(p-1)/2+numtheory[phi](p-1) ;
end proc: # R. J. Mathar, Jan 10 2017
MATHEMATICA
Table[(n - 1)/2 + EulerPhi[n - 1], {n, Prime[Range[2, 100]]}]
PROG
(Magma) [(NthPrime(n)-1)/2+EulerPhi(NthPrime(n)-1): n in [2..100]];
CROSSREFS
Cf. A098006.
Sequence in context: A071349 A282737 A039891 * A363283 A213011 A175265
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jan 10 2017
STATUS
approved