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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A071828 Primes of the form Sum_{i=1..k} (-1)^(k-i)*i!. 9
 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)). MATHEMATICA l = Abs@Accumulate[(-1)^#*#! & /@ Range@99]; l[[Flatten@Position[l, _?PrimeQ]]] (* Hans Rudolf Widmer, Feb 27 2023 *) 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: A321875 A359808 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.

Last modified June 25 17:15 EDT 2024. Contains 373706 sequences. (Running on oeis4.)