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a(n) = 2*p+61+2*gcd(p-1,3)+gcd(p-1,4), where p = prime(n).
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%I #26 Sep 08 2022 08:46:16

%S 68,71,77,83,87,97,101,107,111,125,131,145,149,155,159,173,183,193,

%T 203,207,217,227,231,245,265,269,275,279,289,293,323,327,341,347,365,

%U 371,385,395,399,413,423,433,447,457,461,467,491,515,519,529,533,543,553,567,581,591,605,611,625,629

%N a(n) = 2*p+61+2*gcd(p-1,3)+gcd(p-1,4), where p = prime(n).

%H Vincenzo Librandi, <a href="/A269748/b269748.txt">Table of n, a(n) for n = 1..1000</a>

%H Andrew Misseldine, <a href="http://arxiv.org/abs/1508.03757">Counting Schur Rings over Cyclic Groups</a>, arXiv preprint arXiv:1508.03757 [math.RA], 2015.

%p f1:=proc(n) local p; p:=ithprime(n);

%p 2*p+61+2*gcd(p-1,3)+gcd(p-1,4);

%p end;

%t Table[2 Prime[n] + 61 + 2 GCD[Prime[n] - 1, 3] + GCD[Prime[n] -1, 4], {n, 60}] (* _Vincenzo Librandi_, Mar 26 2016 *)

%o (Magma) [2*p+61 +2*Gcd(p-1,3)+Gcd(p-1,4): p in PrimesUpTo(700)]; // _Vincenzo Librandi_, Mar 26 2016

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Mar 22 2016