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 A051109 Hyperinflation sequence for banknotes. 3

%I

%S 1,2,5,10,20,50,100,200,500,1000,2000,5000,10000,20000,50000,100000,

%T 200000,500000,1000000,2000000,5000000,10000000,20000000,50000000,

%U 100000000,200000000,500000000,1000000000,2000000000,5000000000

%N Hyperinflation sequence for banknotes.

%C Denominations of Polish banknotes circa 1995.

%C English coins in 2006 have denominations of 1, 2, 5, 10, 20, 50, 100, 200 pence.

%F a(3n)=10^n, a(3n+1)=2*10^n, a(3n+2)=5*10^n

%F a(n) = [(n%3)^2 + 1]*10^floor(n/3). E.g. a(0) = [(0%3)^2 + 1]*10^floor(0/3) = [0^2 + 1]*10^0 = 1, a(4) = [(4%3)^2 + 1]*10^floor(4/3) = [1^2 + 1]*10^1 = 20, a(8) = [(8%3)^2 + 1]*10^floor(8/3) = [2^2 + 1]*10^2 = 500. - Justin L. Brown (jlbrown(AT)neo.tamu.edu), Jun 17 2004

%F G.f.: (1+2*x+5*x^2)/(1-10*x^3). - _Philippe Deléham_, Apr 08 2013

%F a(n) = 10*a(n-3) with n>2, a(0)=1, a(1)=2, a(2)=5. - _Philippe Deléham_, Apr 08 2013

%o (Python) print( [ ((n % 3) ** 2 + 1) * 10**int(n/3) for n in range(100)] )

%Y Cf. A117727.

%K easy,nonn

%O 0,2

%A Robert Lozyniak (11(AT)onna.com)

%E Second formula corrected by _Peter C. Lauterbach_, Nov 12 2010

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Last modified October 16 10:19 EDT 2021. Contains 348041 sequences. (Running on oeis4.)