A213407 -id:A213407 - cp's OEIS frontend

A213085 First occurrence of n in A212844.

1, 7, 3, 5, 6, 9, 10, 55, 11, 3521, 246, 21, 52, 89969, 286, 60827, 22, 57481, 1501, 31937, 44, 2977, 49, 27, 40, 39806401, 110, 16777, 114, 214293, 24823, 247, 33, 259274569, 222, 2739, 70, 5993, 253217, 1062899, 72, 2007, 215, 85, 140, 4187, 50, 75

Offset: 0

Alex Ratushnyak, Jul 22 2012

nonn

It is conjectured that every integer n>=0 appears in A212844 at least once, and therefore every a(n) is defined.
Indices of terms that are bigger than 2^32-1 and possibly undefined: 69, 91, 114, 127, 141, 157, 175, 181, 195, 301, 313, 339, ...
Indices 69, 127, 175, 181, 301, 313, 339, ... correspond to terms that either do not exist or are greater than 2*10^12. - Charles R Greathouse IV, Aug 13 2015

			Smallest n such that A212844(n)=1 is 7, so a(1)=7.

Charles R Greathouse IV, Table of n, a(n) for n = 0..68

Cf. A212844, A213381, A213407.

a(n) = my(k=1); while(lift(Mod(2, k)^(k+2)) != n, k++); k; \\ Michel Marcus, Aug 14 2015

A213861 First occurrence of n in A213859.

Original entry on oeis.org

2, 0, 1, 3, 4, 2949, 8, 11, 12, 15, 17, 115, 20, 7863275, 24, 27, 16, 73, 32, 35, 25, 39, 33, 103, 38, 48589961800007, 228, 51, 119, 97, 56, 59, 47, 323, 52, 581, 69, 71, 43, 2277, 77, 17509, 80, 75, 84, 87, 68, 133, 92, 95, 2209, 99, 53, 29363, 104, 107, 6848, 111, 2585, 3241, 116, 449, 120, 7847, 78, 1111, 129, 173, 132, 135, 137, 5340185

Offset: 0

Alex Ratushnyak, Jun 22 2012

nonn

			Smallest n such that A213859(n) = 7 is 11, so a(7) = 11.

Cf. A213859, A213407, A036236

nn = 25; t = Table[-1, {nn}]; Do[p = PowerMod[2, n, n + 2]; If[0 <= p <= nn && t[[p + 1]] == -1, t[[p + 1]] = n], {n, 0, 10^7}]; t (* T. D. Noe, Jun 26 2012 *)

a(n) = smallest k>n such that 2^k == n (mod k+2).

a(26)-a(50) from T. D. Noe, Jun 26 2012

Terms a(25) and a(51) onward from Max Alekseyev, Feb 01 2014

cp's OEIS Frontend

A213085 First occurrence of n in A212844.

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