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A242646
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a(n) = concatenation of decimal expansions of powers of 11 (in increasing order).
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2
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1, 111, 111121, 1111211331, 111121133114641, 111121133114641161051, 1111211331146411610511771561, 111121133114641161051177156119487171, 111121133114641161051177156119487171214358881, 1111211331146411610511771561194871712143588812357947691, 111121133114641161051177156119487171214358881235794769125937424601
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OFFSET
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0,2
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COMMENTS
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a(2) = 111121 is the first prime in this sequence (compare A242645).
There are no further primes through a(100). - Harvey P. Dale, Sep 12 2014
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LINKS
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FORMULA
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a(n) is the concatenation of 1, 11, 121, 11^3, ... 11^(n-1), 11^n.
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MAPLE
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a:= proc(n) option remember;
`if`(n=0, 1, parse(cat(a(n-1), 11^n)))
end:
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MATHEMATICA
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Module[{nn=15, c}, c=IntegerDigits/@(11^Range[0, nn]); Table[FromDigits[ Flatten[ Take[c, n]]], {n, nn+1}]] (* Harvey P. Dale, Sep 12 2014 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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