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

 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!)
 A061009 a(n) = -2 + Sum_{j=1..n} (-(n-1)!) mod n. 3
 -2, -1, 0, 2, 3, 3, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 17, 17, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA a(n) = a(n-1) + A061007(n) = A061008(n) - 2. For n > 3, a(n) = pi(n) = A000720(n) where pi(n) is the number of primes less than or equal to n. EXAMPLE a(6)=3 since -2 + (-1 mod 1) + (-1 mod 2) + (-2 mod 3) + (-6 mod 4) + (-24 mod 5) + (-120 mod 6) = -2 + 0 + 1 + 1 + 2 + 1 + 0 = 3. MAPLE P:=proc(n) local a, i, w; a:=-2; print(a); for i from 1 by 1 to n do w:=((i-1)! mod (i+1)); a:=a+w; print(a); od; end: P(1000); # Paolo P. Lava, Apr 23 2007 CROSSREFS Cf. A000040, A000142, A061006, A061007, A061008. Sequence in context: A104770 A296529 A110280 * A144106 A104558 A206022 Adjacent sequences: A061006 A061007 A061008 * A061010 A061011 A061012 KEYWORD sign AUTHOR Henry Bottomley, Apr 12 2001 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 November 27 09:57 EST 2022. Contains 358367 sequences. (Running on oeis4.)