1,2

Take the sequence of natural numbers:

s0=1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,

Move the first term s(1)=1 to 3*1=3 places to the right:

s1=2,3,4,1,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,

Move the first term s(1)=2 to 3*2=6 places to the right:

s2={3,4,1,5,6,7,2,8,9,10,11,12,13,14,15,16,17,18,19,20,

Repeating the procedure we get successively:

s3={4,1,5,6,7,2,8,9,10,3,11,12,13,14,15,16,17,18,19,20,

s4={1,5,6,7,2,8,9,10,3,11,12,13,4,14,15,16,17,18,19,20,

s5={5,6,7,1,2,8,9,10,3,11,12,13,4,14,15,16,17,18,19,20,

s6={6,7,1,2,8,9,10,3,11,12,13,4,14,15,16,5,17,18,19,20,

s7={7,1,2,8,9,10,3,11,12,13,4,14,15,16,5,17,18,19,6,20,

........................................................................

s100=1,5,39,3,2,40,13,41,42,4,43,9,14,7,44,45,46,6,15,47,10,48,49,16,8,50,

51,52,11,17,53,54,55,18,56,12,57,58,19,59,60,61,20,62,63,64,21,65,66,67,22,

68,69,70,23,71,72,73,24,74,75,76,25,77,78,79,26,80,81,82,27,83,84,85,28,86,

87,88,29,89,90,91,30,92,93,94,31,95,96,97,32,98,99,100,33,101,102,103,34,

104,105,106,35,107,108,109,36,110,111,112,37,113,114,115,38,116,117,

The sequence A104717 gives the first terms in the rearrangements s0,s1,s2,...,s100. Cf. A104705, A104706

s=Range[200]; bb={1}; Do[s=Drop[Insert[s, s[[1]], 2+3 s[[1]]], 1]; bb=Append[bb, s[[1]]], {i, 100}]; bb

Cf. A104705, A104706.

Sequence in context: A129709 A133108 A055441 this_sequence A067003 A117386 A101174

Adjacent sequences: A104714 A104715 A104716 this_sequence A104718 A104719 A104720

easy,nonn

Zak Seidov (zakseidov(AT)yahoo.com), Mar 20 2005