login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A288448 Numbers k such that k!6 + 32 is prime, where k!6 is the sextuple factorial number (A085158 ). 1
5, 9, 17, 21, 29, 53, 57, 105, 111, 279, 303, 435, 483, 677, 1049, 1217, 1395, 9651, 26031, 31937 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding primes are: 37, 59, 967, 8537, 623677, 2229272062357, 38661097149707, ...

a(21) > 50000.

Terms > 29 correspond to probable primes.

LINKS

Table of n, a(n) for n=1..20.

Henri & Renaud Lifchitz, PRP Records. Search for n!6+32.

Joe McLean, Interesting Sources of Probable Primes

OpenPFGW Project, Primality Tester

EXAMPLE

17!6 + 32 = 17*11*5 + 32 = 967 is prime, so 17 is in the sequence.

MATHEMATICA

MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];

Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 32] &]

CROSSREFS

Cf. A007661, A037082, A084438, A123910, A242994.

Sequence in context: A273851 A097538 A001771 * A022341 A255651 A216877

Adjacent sequences:  A288445 A288446 A288447 * A288449 A288450 A288451

KEYWORD

nonn,more

AUTHOR

Robert Price, Jun 09 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 23 01:48 EST 2020. Contains 331166 sequences. (Running on oeis4.)