A038780 -id:A038780 - cp's OEIS frontend

A038779 An intermediate sequence for nonisomorphic circulant directed p^2-graphs, indexed by odd primes p.

10, 70, 700, 104968, 1398500, 268439590, 3817763740, 799645010860, 2573485510942780, 38430716856090160, 131176846748288854980, 30223145490393217217464, 460543169377106318541400, 107646959937860684094362500, 390046338531762979375904093800

Offset: 1

N. J. A. Sloane, May 04 2000

M. Klin, V. A. Liskovets and R. Poeschel, Analytical enumeration of circulant graphs with prime-squared vertices, Sem. Lotharingien de Combin., B36d, 1996, 36 pages.

Cf. A038777.

a(n) = my(p=prime(n+1)); (1/(p-1)) * sumdiv(p-1, r, eulerphi(r) * 2^(2*(p-1)/r)); \\ Michel Marcus, Feb 14 2021

a(p^2) = A038778(p^2) - A038777(p^2) + A038780(p^2).

a(p^2) = (1/(p-1)) * Sum_{r|p-1} phi(r) * 2^(2*(p-1)/r). - Sean A. Irvine, Feb 14 2021

More terms from Valery A. Liskovets, May 09 2001

More terms and offset corrected by Sean A. Irvine, Feb 14 2021

A363997 Position in A088732 of the n-th prime.

Original entry on oeis.org

1, 2, 3, 4, 6, 7, 9, 5, 10, 8, 12, 15, 16, 19, 14, 21, 11, 22, 24, 18, 27, 20, 30, 31, 17, 34, 36, 37, 40, 28, 42, 45, 49, 51, 13, 26, 52, 54, 55, 38, 57, 32, 64, 33, 44, 66, 23, 46, 69, 35, 70, 25, 50, 75, 76, 79, 41, 82, 56, 84, 29, 58, 87, 60, 90, 91, 48

Offset: 1

Clark Kimberling, Jul 11 2023

nonn

Every positive integer occurs exactly once.

			a(7) = 5 because the 7th prime, 19, is the 5th term in A088732.

Cf. A000040, A088732, A038780, A363998.

z= 200; t = Table[k = 1; While[p = n + k*(n + 1); ! PrimeQ[p], k++];
  p, {n, 0, z}];   (* A088732, after Frank M Jackson *)
Flatten[Table[Position[t, Prime[n]], {n, 1, z}]]  (* this sequence *)

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A038779 An intermediate sequence for nonisomorphic circulant directed p^2-graphs, indexed by odd primes p.

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A363997 Position in A088732 of the n-th prime.

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