Search: id:A161830 Results 1-1 of 1 results found. %I A161830 %S A161830 0,1,3,5,9,11,15,19,27,31,35,39,47,53,61,71,89,99,103 %N A161830 Y-toothpick triangle (see Comments lines for definition). %C A161830 Y-toothpick sequence starting at the corner of an infinite hexagon in which its vertex touch an endpoint of the initial Y-toothpick and the two other endpoints are equidistant from the nearest sides of the hexagon. %C A161830 The sequence gives the number of Y-toothpicks in the sieve after n rounds. A161831 (the first differences) gives the number added at the nth round. %C A161830 See the Y-toothpick sequence A160120 for more information about the recursive, fractal-like structure. %Y A161830 Cf. A139250, A160120, A160121, A160406, A160407, A161831, A161832, A161833. %Y A161830 Sequence in context: A075991 A002731 A006046 this_sequence A151922 A104635 A024903 %Y A161830 Adjacent sequences: A161827 A161828 A161829 this_sequence A161831 A161832 A161833 %K A161830 more,nonn %O A161830 0,3 %A A161830 Omar E. Pol (info(AT)polprimos.com), Jun 20 2009 Search completed in 0.001 seconds