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A166257
Odd numbers not of the form prime(k) + phi(prime(k)).
1
1, 7, 11, 15, 17, 19, 23, 27, 29, 31, 35, 39, 41, 43, 47, 49, 51, 53, 55, 59, 63, 65, 67, 69, 71, 75, 77, 79, 83, 87, 89, 91, 95, 97, 99, 101, 103, 107, 109, 111, 113, 115, 119, 123, 125, 127, 129, 131, 135, 137, 139, 143, 147, 149, 151, 153, 155, 159, 161, 163, 167
OFFSET
1,2
LINKS
FORMULA
{1} U {A005408 \ A076274 }. [R. J. Mathar, May 21 2010]
MATHEMATICA
Module[{upto=200}, Complement[Range[1, upto, 2], Table[n+EulerPhi[n], {n, Prime[ Range[PrimePi[upto]]]}]]] (* Harvey P. Dale, Jun 21 2019 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Entries checked by R. J. Mathar, May 21 2010.
STATUS
approved