A117874 -id:A117874 - cp's OEIS frontend

A118481 Primes for which the level is equal to 9 in A117563.

29, 67, 89, 181, 293, 811, 919, 1153, 1801, 2017, 2053, 2113, 2647, 3373, 3469, 3583, 4057, 5153, 5581, 6481, 6553, 7727, 8209, 8447, 8467, 8543, 8867, 9887, 10009, 10477, 11027, 11743, 12601, 13249, 13421, 13729, 13789, 15017, 15391, 17011, 17123, 18919

Offset: 1

Rémi Eismann, May 05 2006

nonn

			Prime(310) has level 9: prime(311) = prime(310)+prime(310) mod(227) = prime(310)+prime(310) mod(2043) = 2063

Remi Eismann, Table of n, a(n) for n=1..10000

Cf. A117563, A117873, A117078, A117874, A006562, A117876, A001359, A118464.

Edited by N. J. A. Sloane, May 14 2006

Term a(19) and beyond from b-file by Andrew Howroyd, Feb 05 2018

A118122 Least prime of level 2n-1 (cf. A117563).

Original entry on oeis.org

5, 11, 17, 509, 29, 83, 41, 79, 887, 59, 109, 71, 331, 193, 383, 190717, 101, 107, 787, 277, 1129, 911, 137, 1181, 149, 463, 1013, 839, 1087, 179, 433, 191, 197, 4093, 349, 503, 2423, 227, 701, 239, 5378731, 587, 601, 439, 269, 6491, 281, 1621, 877, 499

Offset: 1

Rémi Eismann and Robert G. Wilson v, May 12 2006

nonn

			The first occurrence of 1 in A117563 is a(3) which implies the third prime which is 5.
The first occurrence of 3 in A117562 is a(5) which implies the fifth prime which is 11.
The first occurrence of 5 in A117562 is a(7) which implies the seventh prime which is 17, etc.

Cf. A117078, A117563, A117873, A117874, A118481, A118508.

f[n_] := If[n == 1, 0, Block[{p = Prime@n, np = Prime[n + 1]}, (2p - np)/Min@Select[Divisors[2p - np], # >= np - p &]]]; t = Table[0, {100}]; Do[a = (f@n + 1)/2; If[a < 101 && t[[a]] == 0, t[[a]] = Prime@n; Print[{a, n, Prime@n}]], {n, 10^6}]

Levels of primes are defined in A117563. Conjecture: there are an infinite number of prime members at each level.

cp's OEIS Frontend

A118481 Primes for which the level is equal to 9 in A117563.

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A118122 Least prime of level 2n-1 (cf. A117563).

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