A075258 Larger terms of the pairs (a < b) in the sequence {a,b}-> {Max[{a,b}]-Min[{a,b}],k*Min[{a,b}]} with k=3 and the first pair {a=1,b=2}. See A075256.

2, 3, 3, 6, 5, 9, 7, 18, 17, 14, 27, 22, 45, 38, 63, 51, 138, 133, 118, 135, 219, 186, 471, 442, 355, 783, 689, 846, 1221, 1317, 2346, 1811, 4815, 4609, 3991, 5562, 6411, 10275, 8958, 21867, 20198, 15191, 45063, 44893, 44383, 42853, 38263, 41310

Offset

1,1

Comments

Take any pair {a,b}. Each next pair is get by the rule {a,b} -> Sort[{Max[{a,b}]-Min[{a,b}],k*Min[{a,b}]]. Here k=3 and the first {a,b}={1,2}. For k = 2 there is a fixed point {a,b=2a}. For k > 2, are there any limits or cycles of the sequence {for some initial pair {a,b}?

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..1000

Formula

a(n) = A075256(2*n).

Mathematica

ss=Table[0, {j, 100}]; s=ss[[1]]={1, 2}; Do[ss[[i]]=Sort[{Max[s]-Min[s], 3*Min[s]}]; s=ss[[i]], {i, 2, 100}]; Table[Flatten[ss][[i]], {i, 2, 200, 2}]

Prog

(PARI) my(x=1, y=2); print1(y, ", "); for(n=2, 48, my(mx=max(x, y), mi=min(x, y)); x=min(mx-mi, 3*mi); y=max(mx-mi, 3*mi); print1(y, ", ")) \\ Hugo Pfoertner, Mar 21 2020

Crossrefs

Cf. A075256, A075257.

Sequence in context: A333660 A187754 A347732 * A321745 A212629 A127779

Adjacent sequences: A075255 A075256 A075257 * A075259 A075260 A075261

Keyword

nonn

Author

Zak Seidov, Sep 10 2002

Status

approved