A069115 Squarefree part of prime(n)+1 : the smallest number such that a(n)*(prime(n)+1) is a square.

3, 1, 6, 2, 3, 14, 2, 5, 6, 30, 2, 38, 42, 11, 3, 6, 15, 62, 17, 2, 74, 5, 21, 10, 2, 102, 26, 3, 110, 114, 2, 33, 138, 35, 6, 38, 158, 41, 42, 174, 5, 182, 3, 194, 22, 2, 53, 14, 57, 230, 26, 15, 2, 7, 258, 66, 30, 17, 278, 282, 71, 6, 77, 78, 314, 318, 83, 2, 87, 14, 354, 10

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A007913(A008864(n)). - Amiram Eldar, Sep 03 2020

Mathematica

core[n_] := Times @@ (First[#]^Mod[Last[#], 2]& /@ FactorInteger[n]); core /@ (Select[Range[350], PrimeQ] + 1) (* Amiram Eldar, Sep 03 2020 *)

Prog

(PARI) for(n=1, 100, print1(core(prime(n)+1)), ", "))

Crossrefs

Cf. A007913, A008864, A069114.

Sequence in context: A184168 A122913 A289444 * A065275 A071045 A274317

Adjacent sequences: A069112 A069113 A069114 * A069116 A069117 A069118

Keyword

easy,nonn

Author

Benoit Cloitre, Apr 06 2002

Status

approved