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A110394
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a(1) = 1; a(n) = n times (9's complement of a(n-1)).
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3
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1, 16, 249, 3000, 34995, 390024, 4269825, 45841392, 487427463, 5125725360, 53617021029, 556595747640, 5764255280667, 59300426070648, 610493608940265, 6232102256955744, 64054261631752335, 647023290628457952
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OFFSET
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1,2
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COMMENTS
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a(1)=1; a(n)=n*[99...9 - a(n-1)] for n>1 (99...9 and a[n-1] have the same number of digits). - Emeric Deutsch, Jul 31 2005
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LINKS
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EXAMPLE
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a(4) = 4 times 9's complement of a(3) = 4*(999-249) = 3000.
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MAPLE
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s:=proc(m) nops(convert(m, base, 10)) end: a[1]:=1: for n from 2 to 21 do a[n]:=n*(10^s(a[n-1])-1-a[n-1]) od: seq(a[n], n=1..21); # Emeric Deutsch, Jul 31 2005
# second Maple program:
a:= proc(n) option remember; `if`(n=1, 1,
n*(p-> 10^length(p)-1-p)(a(n-1)))
end:
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MATHEMATICA
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nxt[{n_, a_}]:={n+1, (n+1)(FromDigits[PadRight[{}, IntegerLength[a], 9]]-a)}; NestList[nxt, {1, 1}, 20][[;; , 2]] (* Harvey P. Dale, Mar 13 2024 *)
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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