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A105281
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a(0)=0; a(n)=6*a(n-1)+6.
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3
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0, 6, 42, 258, 1554, 9330, 55986, 335922, 2015538, 12093234, 72559410, 435356466, 2612138802, 15672832818, 94036996914, 564221981490, 3385331888946, 20311991333682, 121871948002098, 731231688012594, 4387390128075570, 26324340768453426, 157946044610720562
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OFFSET
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0,2
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COMMENTS
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Number of integers from 0 to (10^n)-1 that lack 0, 1, 2 and 3 as a digit.
Also, a(n) is the expected number of tosses of a single die needed to obtain for the first time a string of n consecutive 6's. - Jean M. Morales, Aug 04 2012
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LINKS
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FORMULA
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a(n) = 7*a(n-1)-6*a(n-2). G.f.: 6*x/((x-1)*(6*x-1)). - Colin Barker, Jan 28 2013
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MAPLE
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MATHEMATICA
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PROG
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(PARI) a(n)=if(n<0, 0, (6^n-1)*6/5)
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CROSSREFS
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KEYWORD
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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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