A263027 - OEIS

%I #52 Sep 08 2022 08:46:14

%S 2,2,3,3,5,3,7,3,7,5,11,3,13,7,5,5,17,7,19,5,7,11,23,3,21,13,19,7,29,

%T 5,31,9,11,17,13,7,37,19,13,5,41,7,43,11,13,23,47,5,43,21,17,13,53,19,

%U 21,7,19,29,59,5,61,31,7,17,13,11,67,17,23,13,71,7

%N a(n) = A002322(n) + 1, where A002322 is Carmichael lambda.

%C The function t(k,n) = A002322(n)+k provides many prime values for k=1: for n up to 1000, for example, it returns 798 primes (with repetitions). On the other hand, for n <= 1000 and odd k from 3 to 11, t(k,n) gives 247, 387, 538, 231, 504 prime values, respectively.

%C Another function of this type is |A002322(n)-119|, which provides 693 prime values for n <= 1000. [_Bruno Berselli_, Oct 14 2015]

%H Antti Karttunen, <a href="/A263027/b263027.txt">Table of n, a(n) for n = 1..5000</a>

%t Table[CarmichaelLambda[n] + 1, {n, 1, 100}]

%o (Magma) [2] cat [CarmichaelLambda(n)+1: n in [2..100]];

%o (PARI) vector(100, n, 1 + lcm(znstar(n)[2])) \\ _Altug Alkan_, Oct 08 2015

%Y Cf. A002322.

%Y Cf. A263028: indices n for which a(n) is prime.

%Y Cf. A263029: indices n for which a(n) is composite.

%Y Cf. also A039649, A296076, A296077.

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Oct 08 2015

%E Edited by _Bruno Berselli_, Oct 14 2015