A023443 a(n) = n - 1.
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73
Offset: 0
Links
- Tanya Khovanova, Recursive Sequences.
- Index entries for linear recurrences with constant coefficients, signature (2,-1).
Programs
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Magma
A023443:= func< n | n-1 >; // G. C. Greubel, Apr 18 2025
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Mathematica
Range[0,80]-1 (* Harvey P. Dale, Apr 05 2012 *) LinearRecurrence[{2,-1},{-1,0},75] (* Ray Chandler, Jul 30 2015 *)
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PARI
a(n)=n-1 \\ Charles R Greathouse IV, Aug 26 2011
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Python
def A023443(n): return n-1 # G. C. Greubel, Apr 18 2025
Formula
From R. J. Mathar, Feb 11 2010: (Start)
a(n) = 2*a(n-1) -a(n-2).
G.f.: (-1+2*x)/(1-x)^2. (End)
E.g.f.: exp(x)*(x - 1). - Stefano Spezia, Feb 14 2025