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A184337
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a(n) is the integer whose decimal representation consists of n 8's followed by n 1's.
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2
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0, 81, 8811, 888111, 88881111, 8888811111, 888888111111, 88888881111111, 8888888811111111, 888888888111111111, 88888888881111111111, 8888888888811111111111, 888888888888111111111111, 88888888888881111111111111
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OFFSET
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0,2
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..200
Richard Blecksmith and Charles Nicol, Monotonic Numbers, Mathematics Magazine, 66, (1993), 257-262.
Index entries for linear recurrences with constant coefficients, signature (111,-1110,1000).
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FORMULA
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a(n) = (8*100^n - 7*10^n - 1)/9.
a(n) = A059482(n)*A002283(n).
G.f.: 9*x*(-9+20*x) / ( (x-1)*(100*x-1)*(10*x-1) ). - R. J. Mathar, Feb 28 2011
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MATHEMATICA
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Table[(8*100^n - 7*10^n - 1)/9, {n, 0, 30}] (* G. C. Greubel, Nov 02 2018 *)
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PROG
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(Magma) [(8*100^n-7*10^n-1)/9: n in [0..20]]; // Vincenzo Librandi, Aug 04 2011
(PARI) vector(30, n, n--; (8*100^n - 7*10^n - 1)/9) \\ G. C. Greubel, Nov 02 2018
(Python)
for n in range(30):
print((8*100**n-7*10**n-1)//9, end=', ')
# Stefano Spezia, Nov 02 2018
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CROSSREFS
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Cf. A098210 (with 1 and 5 instead of 8 and 1).
Cf. A002283, A059482.
Cf. A008591 (digits sums).
Sequence in context: A328089 A186527 A178511 * A034993 A223328 A093281
Adjacent sequences: A184334 A184335 A184336 * A184338 A184339 A184340
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KEYWORD
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nonn,easy,base
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AUTHOR
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Paul Curtz, Feb 13 2011
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STATUS
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approved
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