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A269748 a(n) = 2*p+61+2*gcd(p-1,3)+gcd(p-1,4), where p = prime(n).

%I A269748 #29 Jun 21 2025 15:12:48
%S A269748 68,71,77,83,87,97,101,107,111,125,131,145,149,155,159,173,183,193,
%T A269748 203,207,217,227,231,245,265,269,275,279,289,293,323,327,341,347,365,
%U A269748 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 A269748 a(n) = 2*p+61+2*gcd(p-1,3)+gcd(p-1,4), where p = prime(n).
%H A269748 Vincenzo Librandi, <a href="/A269748/b269748.txt">Table of n, a(n) for n = 1..1000</a>
%H A269748 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.
%F A269748 a(n) = A232106(n) for n>=3. - _R. J. Mathar_, Jun 21 2025
%p A269748 f1:=proc(n) local p; p:=ithprime(n);
%p A269748 2*p+61+2*gcd(p-1,3)+gcd(p-1,4);
%p A269748 end;
%t A269748 Table[2 Prime[n] + 61 + 2 GCD[Prime[n] - 1, 3] + GCD[Prime[n] -1, 4], {n, 60}] (* _Vincenzo Librandi_, Mar 26 2016 *)
%o A269748 (Magma) [2*p+61 +2*Gcd(p-1,3)+Gcd(p-1,4): p in PrimesUpTo(700)]; // _Vincenzo Librandi_, Mar 26 2016
%K A269748 nonn
%O A269748 1,1
%A A269748 _N. J. A. Sloane_, Mar 22 2016