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A336372 Primes prime(k) such that gcd(k, prime(k) + prime(k-1)) = 1. 3

%I #16 Jul 19 2023 15:17:56

%S 3,5,11,17,31,59,67,83,97,109,127,137,149,157,179,191,211,227,241,257,

%T 277,283,331,353,367,379,389,401,431,439,449,461,467,509,547,563,587,

%U 599,607,617,653,691,709,739,751,773,797,823,829,859,877,907,919,947

%N Primes prime(k) such that gcd(k, prime(k) + prime(k-1)) = 1.

%C This sequence and A336373 partition the set of odd primes.

%e In the following table, p(n) = A000040(n) = prime(n).

%e n p(n) p(n)+p(n-1) gcd

%e 2 3 5 1

%e 3 5 8 1

%e 4 7 12 4

%e 5 11 18 1

%e 6 13 24 6

%t p[n_] := Prime[n];

%t u = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] == 1 &] (* A336370 *)

%t v = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] > 1 &] (* A336371 *)

%t Prime[u] (* this sequence *)

%t Prime[v] (* A336373 *)

%Y Cf. A000040, A001043, A336366, A336370, A336371, A336373.

%K nonn

%O 1,1

%A _Clark Kimberling_, Oct 05 2020

%E Offset corrected by _Mohammed Yaseen_, Jun 02 2023

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Last modified April 25 07:41 EDT 2024. Contains 371964 sequences. (Running on oeis4.)