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A066547
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Let N = 123456789101112131415161718..., the concatenation of the natural numbers. a(n) is the n-digit number formed from the digits of N starting from the {n(n-1)/2 +1}th digit. Omit any leading zeros.
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11
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1, 23, 456, 7891, 1112, 131415, 1617181, 92021222, 324252627, 2829303132, 33343536373, 839404142434, 4454647484950, 51525354555657, 585960616263646, 5666768697071727, 37475767778798081, 828384858687888990, 9192939495969798991, 101102103104105106, 107108109110111112113
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OFFSET
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1,2
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LINKS
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EXAMPLE
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1, 23, 456, 7891, 01112, 131415, 1617181, 92021222, 3... becomes 1, 23, 456, 7891, 1112, 131415, 1617181, 92021222, ...
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MATHEMATICA
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d = Flatten[IntegerDigits /@ Range[90]]; Table[FromDigits[Take[d, {n(n + 1)/2 + 1, (n + 1)(n + 2)/2}]], {n, 0, 17}] (* Robert G. Wilson v, Nov 22 2004 *)
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PROG
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(PARI) N=[]; k=0; for(n=1, 20, while(#N<n, N=concat(N, Vec(Str(k++)))); print1(eval(concat(vecextract(N, 2^n-1)))", "); N=vecextract(N, Str("^.."n))) \\ M. F. Hasler, May 08 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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EXTENSIONS
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More terms from Larry Reeves (larryr(AT)acm.org), Dec 18 2001
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STATUS
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approved
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