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Search: id:A007908
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| A007908 |
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Concatenation of the numbers from 1 to n. |
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+0
79
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| 1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789, 12345678910, 1234567891011, 123456789101112, 12345678910111213, 1234567891011121314, 123456789101112131415, 12345678910111213141516, 1234567891011121314151617
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Sometimes called Smarandache consecutive numbers.
Also called the triangle of the gods (see Pickover link).
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REFERENCES
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Y. Guo and M. Le, Smarandache Concatenated Power Decimals and Their Irrationality, Smarandache Notions Journal, Vol. 9, No. 1-2. 1998, 100-102.
R. K. Guy, Unsolved Problems in Number Theory, A3.
F. Smarandache, "Only Problems, not Solutions!", Xiquan Publ., Phoenix-Chicago, 1993.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..100
M. L. Perez et al., eds., Smarandache Notions Journal
Clifford Pickover, Triangle of the Gods
R. W. Stephan, Factors and primes in two Smarandache sequences
F. Smarandache, Only Problems, Not Solutions!
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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FORMULA
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a(n)=a(n-1)*10^floor[log10(10*n)]+n - Paolo P. Lava (ppl(AT)spl.at), Feb 01 2008
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CROSSREFS
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See A057137 for another version.
Adjacent sequences: A007905 A007906 A007907 this_sequence A007909 A007910 A007911
Sequence in context: A014824 A060555 A138957 this_sequence A057932 A132943 A134802
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KEYWORD
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nonn,base
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AUTHOR
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R. Muller
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