A174408 Primes of the form A174335(i)-1 or A174335(i)+1.

17, 257, 2591, 2593, 239999, 2488319, 27659519, 27659521, 330301441, 4232632319, 58060799999, 13243436236801, 70614415872000001, 3429209878281350809286344704000001, 1665505492033205854772229590583093971095149084672000000001

Offset

1,1

Links

Table of n, a(n) for n=1..15.

Formula

a(n) = {A000040(i)} INTERSECTION ({16*(j^3)*(j!) - 1} UNION {16*(k^3)*(k!) - 1}).

Example

a(1)  =                17 = 16 *  1^3 *  1! + 1 is prime.
a(2)  =               257 = 16 *  2^3 *  2! + 1 is prime.
a(3)  =              2591 = 16 *  3^3 *  3! - 1 is prime.
a(4)  =              2593 = 16 *  3^3 *  3! + 1 is prime.
a(5)  =            239999 = 16 *  5^3 *  5! - 1 is prime.
a(6)  =           2488319 = 16 *  6^3 *  6! - 1 is prime.
a(7)  =          27659519 = 16 *  7^3 *  7! - 1 is prime.
a(8)  =          27659521 = 16 *  7^3 *  7! + 1 is prime.
a(9)  =         330301441 = 16 *  8^3 *  8! + 1 is prime.
a(10) =        4232632319 = 16 *  9^3 *  9! - 1 is prime.
a(11) =       58060799999 = 16 * 10^3 * 10! - 1 is prime.
a(12) =    13243436236801 = 16 * 12^3 * 12! + 1 is prime.
a(13) = 70614415872000001 = 16 * 15^3 * 15! + 1 is prime.

Maple

A174335 := proc(n) 16*n^3*n! ; end proc: for i from 1 to 60 do a := A174335(i) ; if isprime(a-1) then printf("%d, ", a-1) ; end if; if isprime(a+1) then printf("%d, ", a+1) ; end if; end do: # R. J. Mathar, Apr 15 2010

Crossrefs

Cf. A000040, A000142, A000578, A174335.

Sequence in context: A342481 A355876 A337846 * A260072 A260407 A193329

Adjacent sequences: A174405 A174406 A174407 * A174409 A174410 A174411

Keyword

easy,nonn

Author

Jonathan Vos Post, Mar 19 2010

Extensions

One more term from R. J. Mathar, Apr 15 2010

Status

approved