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 A101620 Decimal encoding of digraph topologies. 0
 1, 3, 9, 11, 13, 15, 129, 131, 133, 137, 139, 141, 143, 145, 153, 161, 163, 165, 171, 175, 177, 179, 187, 193, 195, 197, 205, 207, 209, 213, 221, 241, 243, 245, 255 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The sequence encodes labeled digraph topologies as described by and counted in A000798. LINKS Table of n, a(n) for n=1..35. EXAMPLE Let a = 2, b = 4, c = 16, d = 256, ... a(19) = 171 because we can map { }, a, ab, ac, abc to 1 + 2 + 8 + 32 + 128 Viewed as an array the table begins 1 3 9 11 13 15 129 131 133 137 139 141 143 145 153 161 163 165 171 175 177 ... with respectively 1 1 4 29 355 ... (A000798) entries on each row. CROSSREFS Cf. A000798, A001035, A001930, A074486. Sequence in context: A074261 A059868 A101735 * A235583 A287333 A174813 Adjacent sequences: A101617 A101618 A101619 * A101621 A101622 A101623 KEYWORD more,nonn,tabf,base AUTHOR Alford Arnold, Dec 10 2004 STATUS approved

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Last modified December 5 21:07 EST 2023. Contains 367594 sequences. (Running on oeis4.)