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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157833 Numbers n such that 1 + sum_{k=0..n} (-1)^k*(n-k)! is prime. 0
2, 3, 5, 7, 15, 19, 41, 59, 61, 105, 661, 2653, 3069, 3943, 4053 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Note that when n is even, 3 divides the sum.

The sums corresponding to terms >= 661 are only probable primes. - Klaus Brockhaus, Mar 13 2009

LINKS

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

EXAMPLE

a(2)=((-1)^0)(2-0)!+((-1)^1)(2-1)!+((-1)^2)(2-2)!+1=2!-1!+0!+1= 3 (prime).

CROSSREFS

Sequence in context: A303875 A331037 A228652 * A175758 A151531 A079987

Adjacent sequences:  A157830 A157831 A157832 * A157834 A157835 A157836

KEYWORD

nonn

AUTHOR

Kyle D. Balliet, Mar 07 2009

EXTENSIONS

a(7) - a(15) from Klaus Brockhaus, Mar 13 2009

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 February 22 17:14 EST 2020. Contains 332140 sequences. (Running on oeis4.)