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A067870
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Numbers n such that n and 3^n end with the same digit.
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0
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7, 13, 27, 33, 47, 53, 67, 73, 87, 93, 107, 113, 127, 133, 147, 153, 167, 173, 187, 193, 207, 213, 227, 233, 247, 253, 267, 273, 287, 293, 307, 313, 327, 333, 347, 353, 367, 373, 387, 393, 407, 413, 427, 433, 447, 453, 467, 473, 487, 493, 507, 513, 527, 533
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 3^13=1594323 hence 13 is in the sequence
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FORMULA
| a(2n+1)=20n-13 a(2n)=20n-7
a(n)=20*(n-1)-a(n-1) (with a(1)=7) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 08 2010]
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EXAMPLE
| a(2)=20*1-7=13; a(3)=20*2-13=27; a(4)=20*3-27=33 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 08 2010]
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CROSSREFS
| Sequence in context: A060455 A205541 A072579 * A147258 A146718 A146646
Adjacent sequences: A067867 A067868 A067869 * A067871 A067872 A067873
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KEYWORD
| easy,nonn,base
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 07 2002
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