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Search: id:A002477
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| A002477 |
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Wonderful Demlo numbers.
(Formerly M5386 N2339)
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+0
19
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| 1, 121, 12321, 1234321, 123454321, 12345654321, 1234567654321, 123456787654321, 12345678987654321, 1234567900987654321, 123456790120987654321, 12345679012320987654321, 1234567901234320987654321
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Inverse function to A002275. - Odimar Fabeny (aifab(AT)yahoo.com.br), Apr 27 2008
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REFERENCES
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D. R. Kaprekar, On Wonderful Demlo numbers, Math. Stud., 6 (1938), 68.
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LINKS
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S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures}, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Eric Weisstein's World of Mathematics, Repunit
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FORMULA
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G.f.: x(1+10x) / ((1-x)(1-10x)(1-100x)).
a(n) = ((10^(n+1)-1)/9)^2 = A000042^2
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MAPLE
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A002477:=-(1+10*z)/(z-1)/(100*z-1)/(10*z-1); [S. Plouffe in his 1992 dissertation.]
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CROSSREFS
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Cf. A002275.
Sequence in context: A137466 A062689 A057139 this_sequence A068117 A080162 A030174
Adjacent sequences: A002474 A002475 A002476 this_sequence A002478 A002479 A002480
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KEYWORD
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nonn,easy
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AUTHOR
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njas
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