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A053422
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n times (n 1's): n*(10^n - 1)/9.
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7
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0, 1, 22, 333, 4444, 55555, 666666, 7777777, 88888888, 999999999, 11111111110, 122222222221, 1333333333332, 14444444444443, 155555555555554, 1666666666666665, 17777777777777776, 188888888888888887, 1999999999999999998, 21111111111111111109, 222222222222222222220, 2333333333333333333331
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| R_a(n) is the least repunit divisible by the square of R_n = (10^n - 1)/9. - Lekraj Beedassy (blekraj(AT)yahoo.com), Jun 07 2006
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FORMULA
| a(n) = n*A002275(n) = a(n-1)*10n/(n-1)+n
O.g.f.: -x(-1+10x^2)/((-1+x)^2*(-1+10x)^2) . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 21 2008
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PROG
| (Other) sage: [gaussian_binomial(n, 1, 10)*n for n in xrange(0, 22)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 29 2009]
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CROSSREFS
| Cf. A000461, A048376.
Sequence in context: A025936 A158849 A048376 * A000461 A048795 A068186
Adjacent sequences: A053419 A053420 A053421 * A053423 A053424 A053425
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KEYWORD
| base,easy,nonn
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AUTHOR
| Henry Bottomley (se16(AT)btinternet.com), Mar 07 2000
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EXTENSIONS
| Corrected by Jason Earls (zevi_35711(AT)yahoo.com), Sep 02 2006
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