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A050607
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Numbers n such that base 5 expansion matches (0|1|2)*((0|1)(3|4))?(0|1|2)*
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3
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 17, 20, 21, 22, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 40, 41, 42, 45, 46, 47, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 75, 76, 77, 80, 81, 82, 85, 86, 87, 100, 101, 102, 105, 106, 107, 110, 111, 112, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 140, 141, 142, 145
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| 25 does not divide C(2s-1,s) = A001700[ s ] (nor C(2s,s) = A000984[ s ], central column of Pascal's Triangle) if and only if s is one of the terms in this sequence.
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PROG
| (Perl) sub conv_x_base_n { my($x, $b) = @_; my ($r, $z) = (0, '');
do { $r = $x % $b; $x = ($x - $r)/$b; $z = "$r" . $z; } while(0 != $x);
return($z); }
for($i=1; $i <= 201; $i++) { if(("0" . conv_x_base_n($i, 5)) =~ /^(0|1|2)*((0|1)(3|4))?(0|1|2)*$/) { print $i, ", "; } }
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CROSSREFS
| Cf. A037453, A046097, A050608.
Sequence in context: A003964 A023781 A135578 * A180477 A083970 A071204
Adjacent sequences: A050604 A050605 A050606 * A050608 A050609 A050610
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KEYWORD
| nonn
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AUTHOR
| Antti Karttunen Oct 24 1999
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