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Search: id:A060630
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| A060630 |
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For n > 9 let f(n) be formed by writing down the sums of every pair of consecutive digits of n: e.g. f(3469)=71015 because 3+4=7,4+6=10,6+9=15; let f(n)=0 if n is a single digit. Sequence gives smallest number requiring n iterations to reach zero. |
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+0
2
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| 0, 1, 10, 19, 109, 149, 197, 399, 694, 796, 893, 897, 1167, 1579, 1596, 1667, 1790, 1777, 2859, 1779, 1778, 1873, 3679, 5926, 11289, 9539, 13551, 4589, 5960, 12066, 12265, 19119, 10927, 12379, 11742, 65220, 34038, 40390, 1110025, 10100023
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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24-th and 26-th terms are unknown, but a(25)=9539, a(27)=4589 and a(28)=5960.
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LINKS
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Erich Friedman, Problem of the Month (Feb 2000)
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FORMULA
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a(n)=10^(n-2)+9, for n=2, 3, 4 and for n > 40
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EXAMPLE
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a(5)=149 because 149 -(1)-> 513 -(2)-> 64 -(3)-> 10 -(4)-> 1 -(5)-> 0. a(7)=399 because 399 -(1)-> 1218 -(2)-> 339 -(3)-> 612 -(4)-> 73 -(5)-> 10 -(6)-> 1 -(7)-> 0.
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CROSSREFS
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Sequence in context: A007811 A166706 A131495 this_sequence A070199 A015445 A123001
Adjacent sequences: A060627 A060628 A060629 this_sequence A060631 A060632 A060633
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KEYWORD
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base,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Apr 14 2001
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EXTENSIONS
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More terms from Berend Jan van der Zwaag, Jun 23 2001
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