A217558 Split-and-swap on 8-bit integers.

0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 1, 17, 33, 49, 65, 81, 97, 113, 129, 145, 161, 177, 193, 209, 225, 241, 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162, 178, 194, 210, 226, 242, 3, 19, 35, 51, 67, 83, 99, 115, 131, 147, 163, 179, 195, 211, 227, 243

Offset: 0

Author

Jon Perry, Oct 06 2012

Keywords

• nonn
• fini
• full
• base

Comments

Split-and-swap consists of spliting a binary word into two halves and swapping the parts over to form a new word, for example 11001010 becomes 10101100.

There are 256 terms to the sequence. - Harvey P. Dale, Jul 14 2015

Fixed points are the multiples of 17 (A008599) in {0..255}. - Alois P. Heinz, May 02 2024

Examples

			a(17)=17 because 17 is 00010001 which is invariant over the SaS rule.
a(19)=49 because 00010011 becomes 00110001.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..255

Crossrefs

Cf. A008599.

Programs

JavaScript

for (i=0;i<16;i++)
for (j=0;j<16;j++)
document.write(j*16+i+", ");

Mathematica

FromDigits[#,2]&/@(Join[Take[#,-4],Take[#,4]]&/@Select[Tuples[{0,1},8], Length[#] ==8 &]) (* Harvey P. Dale, Jul 14 2015 *)

PARI

A217558(n)=[1,16]*divrem(n,16) \\ - M. F. Hasler, Oct 07 2012