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A073445 Second differences of A002808, the sequence of composites. 3
0, -1, 0, 1, 0, -1, 0, 1, 0, -1, 0, 1, -1, 0, 0, 0, 1, 0, -1, 0, 0, 0, 1, -1, 0, 1, 0, -1, 0, 1, -1, 0, 0, 0, 1, -1, 0, 0, 0, 1, 0, -1, 0, 0, 0, 1, -1, 0, 1, 0, -1, 0, 0, 0, 1, -1, 0, 1, -1, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 1, -1, 0, 1, 0, -1, 0, 1, 0, -1, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 1, -1, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n)=c[n+2]-2c[n+1])+c[n], where c(n)=A002808(n).
a(n) = A073783(n+1) - A073783(n). - Reinhard Zumkeller, Jan 10 2013
MATHEMATICA
c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] Table[(c[w+2]-2*c[w+1])+c[w]), {w, 1, 1000}]
PROG
(Haskell)
a073445 n = a073445_list !! (n-1)
a073445_list = zipWith (-) (tail a073783_list) a073783_list
-- Reinhard Zumkeller, Jan 10 2013
CROSSREFS
Also first differences of A054546.
Sequence in context: A134452 A327515 A327532 * A285589 A179081 A113217
KEYWORD
sign
AUTHOR
Labos Elemer, Aug 01 2002
STATUS
approved

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Last modified March 19 07:49 EDT 2024. Contains 370958 sequences. (Running on oeis4.)