A128886 - OEIS

%I #15 Nov 18 2019 03:18:26

%S -1,-2,4,2,4,-2,4,22,28,4,16,2,22,14,70,48,28,40,12,2,34,24,36,42,24,

%T 16,88,82,96,68,10,46,52,70,30,28,106,84,82,62,56,78,82,106,114,118,

%U 18,-40,52,66,68,52,136,70,46,52,54,64,112,78,114,94,10,50,82,82,4,136,90,74

%N a(n) = prime(lucky(n)) - lucky(prime(n)).

%C Commutator [prime,lucky] = [A032605, A032606].

%H Amiram Eldar, <a href="/A128886/b128886.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A000040(A000959(n)) - A000959(A000040(n)).

%e a(1) = Prime(Lucky(1)) - Lucky(Prime(1)) = Prime(1) - Lucky(2) = 2 - 3 = -1.

%e a(2) = Prime(Lucky(2)) - Lucky(Prime(2)) = Prime(3) - Lucky(3) = 5 - 7 = -2.

%e a(3) = Prime(Lucky(3)) - Lucky(Prime(3)) = Prime(7) - Lucky(5) = 17 - 13 = 4.

%o (Perl) use ntheory ":all"; say "$_ ", nth_prime(nth_lucky($_))-nth_lucky(nth_prime($_)) for 1..20; # _Dana Jacobsen_, Dec 21 2018

%Y Cf. A000040, A000959, A032605 (Prime numbers indexed by lucky numbers), A032606 (Lucky numbers indexed by prime numbers).

%K easy,sign

%O 1,2

%A _Jonathan Vos Post_, May 08 2007

%E Entries corrected starting at a(10) by _R. J. Mathar_, Oct 22 2010