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A095372
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1+integers repeating "90" decimal digit pattern:.
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5
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1, 91, 9091, 909091, 90909091, 9090909091, 909090909091, 90909090909091, 9090909090909091, 909090909090909091, 90909090909090909091, 9090909090909090909091, 909090909090909090909091
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| These numbers arise for example as divisors of several repunits (A002275).
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FORMULA
| a(n) = 1+90*(-1+100^n)/99 = (10^(2n+1)+1)/11. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Aug 01 2004
a(n)=[a(n-1)-1]*100+91, with a(0)=1 [From Paolo P. Lava (paoloplava(AT)gmail.com), Oct 21 2008]
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EXAMPLE
| Digit-pattern P=[ab..z] repeating integers equal formally with P*(-1+10^(Ln))/(-1+10^L), where L is the length of pattern;
a(9) divides A002275(38) repunit. See A095371.
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MATHEMATICA
| Table[1+90*(100^n-1)/99, {n, 0, 20}]
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CROSSREFS
| Cf. A002275, A095371.
Cf. A015585, A097209, A001562, A054416.
Sequence in context: A006244 A054216 A109627 * A165154 A015261 A168624
Adjacent sequences: A095369 A095370 A095371 * A095373 A095374 A095375
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KEYWORD
| easy,nonn,base
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Jun 07 2004
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