Search: id:A131388 Results 1-1 of 1 results found. %I A131388 %S A131388 1,2,4,3,6,10,8,5,11,7,12,19,14,22,16,9,18,28,20,31,21,33,24,13,26,40, %T A131388 27,15,30,46,32,17,34,52,36,55,38,58,39,60,42,64,44,23,47,25,48,73,50, %U A131388 76,51,78,54,82,56,29,59,88,57,89,61,92,63,96,66,100,68,35,70,106,72,37 %N A131388 Conjectured permutation of the positive integers using Rule 1 with a(1)=1. %C A131388 Conjecture 1: a( ) is a permutation of the positive integers. Conjecture 2: d( ) is a permutation of the integers. The sequence using "Rule 2" (positive before negative) is A131393. %F A131388 Rule 1 ("negative before positive"): define sequences d( ) and a( ) as follows: d(1)=0, a(1)=1 and for n>=2, d(n) is the greatest negative integer d such that a(n-1)+d is not among a(1), a(2),...,a(n-1), or, if no such d exists, then d(n) is the least positive integer d such that a(n-1)+d is not among a(1), a(2),...,a(n-1). Then a(n)=a(n-1)+d. %e A131388 a(2)=1+1, a(3)=a(2)+2, a(4)=a(3)+(-1), a(5)=a(4)+3, a(6)=a(5)+4. %Y A131388 Cf. A131389, A131390, A131391, A131392, A131393, A131394, A131395, A131396, A131397. %Y A131388 Sequence in context: A113233 A051849 A083673 this_sequence A131393 A002326 A064273 %Y A131388 Adjacent sequences: A131385 A131386 A131387 this_sequence A131389 A131390 A131391 %K A131388 nonn %O A131388 1,2 %A A131388 Clark Kimberling (ck6(AT)evansville.edu), Jul 05 2007 Search completed in 0.001 seconds