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Search: id:A116123
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| A116123 |
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Numbers n such that n concatenated with n-5 gives the product of two numbers which differ by 4. |
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+0
6
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| 82, 8242, 9802, 538277, 998002, 77837026, 99980002, 7922547265, 8643251345, 9223797610, 9999800002, 106710893290, 453378226757, 491023832065, 945958034530, 999998000002, 11916002265170, 15790977390245
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OFFSET
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1,1
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COMMENT
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If n-1 and n-5 have the same number of digits, then n is also in A054214 because n//n-5=10^d*n+n-5=k(k+4) then implies a representation n//n-1=k(k+4)+4=(k+2)^2. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 10 2008]
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EXAMPLE
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9999800002//9999799997 = 9999899999 * 9999900003, where // denotes concatenation.
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CROSSREFS
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Cf. A116117, A116122, A116124, A116129, A116254.
Adjacent sequences: A116120 A116121 A116122 this_sequence A116124 A116125 A116126
Sequence in context: A035736 A017745 A097841 this_sequence A116142 A054214 A093241
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KEYWORD
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nonn,base
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AUTHOR
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Giovanni Resta (g.resta(AT)iit.cnr.it), Feb 06 2006
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