login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071828 Primes of the form Sum_{i=1..k} (-1)^(k-i)*i!. 7
5, 19, 101, 619, 4421, 35899, 3301819, 1226280710981, 115578717622022981, 32656499591185747972776747396512425885838364422981 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..14

M. Zivkovic, The number of primes sum_(i=1..n)(-1)^(n-i)i! is finite, Math. Comp. vol 68 (1999) pp 403-409.

FORMULA

a(n) = A005165(A001272(n)).

PROG

(PARI) for(n=1, 120, if(isprime(abs(sum(i=1, n, (-1)^i*i!)))==1, print1(abs(sum(i=1, n, (-1)^i*i!)), ", ")))

(PARI) v=[]; for(n=1, 1000, if(ispseudoprime(t=abs(sum(i=1, n, (-1)^i*i!))), v=concat(v, t))); v \\ Charles R Greathouse IV, Feb 14 2011

CROSSREFS

Cf. A001272, A005165.

Sequence in context: A162292 A321875 A005165 * A280067 A158615 A321652

Adjacent sequences: A071825 A071826 A071827 * A071829 A071830 A071831

KEYWORD

nonn,fini

AUTHOR

Benoit Cloitre, Jun 08 2002

EXTENSIONS

Edited by R. J. Mathar, Aug 28 2007

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 21:00 EST 2022. Contains 358648 sequences. (Running on oeis4.)