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a(n) = n-th prime modulo 28.
2

%I #11 Dec 13 2024 10:25:01

%S 2,3,5,7,11,13,17,19,23,1,3,9,13,15,19,25,3,5,11,15,17,23,27,5,13,17,

%T 19,23,25,1,15,19,25,27,9,11,17,23,27,5,11,13,23,25,1,3,15,27,3,5,9,

%U 15,17,27,5,11,17,19,25,1,3,13,27,3,5,9,23,1,11,13,17,23

%N a(n) = n-th prime modulo 28.

%H Vincenzo Librandi, <a href="/A242126/b242126.txt">Table of n, a(n) for n = 1..1000</a>

%F Sum_k={1..n} a(k) ~ 14*n. - _Amiram Eldar_, Dec 13 2024

%t Mod[Prime[Range[100]], 28]

%o (Magma) [p mod(28): p in PrimesUpTo(500)];

%o (Sage) [mod(p, 28) for p in primes(500)] # _Bruno Berselli_, May 05 2014

%Y Cf. similar sequences listed in A242119.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, May 05 2014