A272476 a(n) = n if n is prime, a(n) = 2*n+3 otherwise.

3, 5, 2, 3, 11, 5, 15, 7, 19, 21, 23, 11, 27, 13, 31, 33, 35, 17, 39, 19, 43, 45, 47, 23, 51, 53, 55, 57, 59, 29, 63, 31, 67, 69, 71, 73, 75, 37, 79, 81, 83, 41, 87, 43, 91, 93, 95, 47, 99, 101, 103, 105, 107, 53, 111, 113, 115, 117, 119, 59, 123, 61, 127

Offset

0,1

Comments

Prime numbers repeated: 3, 5, 11, 19, 23, 31, 43, 47, 53, 59, 67, 71, ..., that is A065091 without A089531.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Mathematica

Table[If[PrimeQ[n], n, 2 n + 3], {n, 0, 150}]

Prog

(Magma) [IsPrime(n) select n else 2*n+3: n in [0..80]];

Crossrefs

Cf. A000040, A018252.

Cf. A061397, A191558.

Sequence in context: A241429 A200109 A156060 * A205701 A218888 A261597

Adjacent sequences: A272473 A272474 A272475 * A272477 A272478 A272479

Keyword

nonn,easy

Author

Vincenzo Librandi, May 02 2016

Status

approved