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 A050608 Numbers n such that base 7 expansion matches (0|1|2|3)*((0|1|2)(4|5|6))?(0|1|2|3)* 4
 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 28, 29, 30, 31, 35, 36, 37, 38, 42, 43, 44, 45, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 77, 78, 79, 80, 84, 85, 86, 87, 91, 92, 93, 94, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 49 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. LINKS PROG (Perl) For conv_x_base_n function, see A050607. (Perl) for(\$i=1; \$i <= 1000; \$i++) { if(("0" . conv_x_base_n(\$i, 7)) =~ /^(0|1|2|3)*((0|1|2)(4|5|6))?(0|1|2|3)*\$/) { print \$i, ", "; } } CROSSREFS Cf. A037461, A046097, A050607. Sequence in context: A246091 A175427 A246098 * A260424 A046510 A090273 Adjacent sequences:  A050605 A050606 A050607 * A050609 A050610 A050611 KEYWORD nonn,easy,base AUTHOR Antti Karttunen, 1999 STATUS approved

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Last modified May 12 07:28 EDT 2021. Contains 343821 sequences. (Running on oeis4.)