A121236 Primes of the form A001228(n) + 1 and A001228(n) - 1 where A001228 = orders of sporadic simple groups.

7919, 604801, 10200959, 44351999, 44352001, 50232961, 244823041, 460815505919, 64561751654399, 4089470473293004801, 4157776806543360001, 86775571046077562879

Offset

1,1

Comments

This is not an arbitrary thing to do, as in some cases the sporadic group has an order depending on a specific power, as with A001228(1) + 1 = 7921 = 89^2 and A001228(3) + 1 = 175561 = 419^2. The largest integer to check is 1 + the order of the monster group, which is the semiprime 808017424794512875886459904961710757005754368000000001 = 18250906752127213 * 44272727693397225537389001926419074277.

Links

Table of n, a(n) for n=1..12.

Formula

({A001228(n) + 1} UNION {A001228(n) - 1}) INTERSECTION A000040.

Example

a(1) = 7919 = A001228(1) - 1.
a(2) = 604801 = A001228(5) + 1.
a(3) = 10200959 = A001228(6) - 1.
a(4) = 44351999 = A001228(7) - 1.
a(5) = 44352001 = A001228(7) + 1.
a(6) = 50232961 = A001228(8) + 1.
a(7) = 244823041 = A001228(9) + 1.
a(8) = 460815505919 = A001228(14) + 1.
a(9) = 64561751654399 = A001228(17) - 1.
a(10) = 4089470473293004801 = A001228(21) + 1.
a(11) = 4157776806543360001 = A001228(22) + 1.
a(12) = 86775571046077562879 = A001228(23) - 1.

Crossrefs

Cf. A000040, A001228.

Sequence in context: A171111 A155178 A031922 * A233976 A001228 A036325

Adjacent sequences: A121233 A121234 A121235 * A121237 A121238 A121239

Keyword

easy,fini,full,nonn

Author

Jonathan Vos Post, Aug 21 2006

Status

approved