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 A275059 Numbers n such that A000010(n) + n^2 is a prime. 1
 1, 2, 3, 5, 11, 13, 15, 19, 31, 33, 35, 41, 51, 53, 59, 65, 83, 89, 91, 101, 103, 115, 131, 141, 149, 161, 163, 181, 185, 187, 191, 193, 199, 217, 221, 233, 241, 263, 281, 287, 295, 303, 329, 331, 349, 373, 401, 415, 419, 431, 433, 445, 449, 461, 463, 469, 473, 499, 517 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For n >= 2, a(n) is odd and squarefree. - Robert Israel, Jul 29 2016 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE 5 is a term because A000010(5) + 5^2 = 29 is a prime number. MAPLE select(t -> isprime(numtheory:-phi(t) + t^2), [1, 2, seq(n, n=3..1000, 2)]); # Robert Israel, Jul 29 2016 MATHEMATICA Select[Range[2000], PrimeQ[#^2 + EulerPhi[#]] &] PROG (Magma) [n: n in [1..800] | IsPrime(n^2+EulerPhi(n))]; (PARI) isok(n) = isprime(eulerphi(n) + n^2); \\ Altug Alkan, Jul 27 2016 CROSSREFS Cf. A000010, A259145. Sequence in context: A269004 A100475 A187921 * A072538 A225856 A322173 Adjacent sequences: A275056 A275057 A275058 * A275060 A275061 A275062 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Jul 27 2016 STATUS approved

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Last modified August 7 06:05 EDT 2024. Contains 375008 sequences. (Running on oeis4.)