A269749 a(n) = 3*p^2+39*p+344+24*gcd(p-1,3)+11*gcd(p-1,4)+2*gcd(p-1,5), where p = prime(n).

471, 536, 684, 860, 1192, 1476, 1944, 2264, 2876, 4068, 4540, 6012, 7064, 7664, 8852, 10908, 13136, 14012, 16520, 18292, 19296, 22244, 24296, 27648, 32472, 34964, 36284, 38912, 40356, 43128, 53780, 56992, 62064, 63824, 72828, 74740, 80532, 86504, 90572, 96948, 103496, 105812, 117292, 119736

Offset: 1

Author

N. J. A. Sloane, Mar 22 2016

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• Andrew Misseldine, Counting Schur Rings over Cyclic Groups, arXiv preprint arXiv:1508.03757 [math.RA], 2015.

Programs

Magma

[3*p^2 + 39*p + 344 + 24*Gcd(p-1, 3) + 11*Gcd(p-1, 4) + 2*Gcd(p-1, 5): p in PrimesUpTo(200)]; // Vincenzo Librandi, Mar 26 2016

Maple

f2:=proc(n) local p; p:=ithprime(n);
3*p^2+39*p+344+24*gcd(p-1,3)+11*gcd(p-1,4)+2*gcd(p-1,5);
end;
[seq(f2(n),n=1..60)];

Mathematica

Table[3 Prime[n]^2 + 39 Prime[n] + 344 + 24 GCD[Prime[n] - 1, 3]+ 11 GCD[Prime[n] - 1, 4] + 2 GCD[Prime[n] - 1, 5], {n, 45}] (* Vincenzo Librandi, Mar 26 2016 *)

Formula

a(n) = A232106(n), n>2. - R. J. Mathar, May 23 2016