|
|
A279260
|
|
Numbers which are cyclops palindromic in their binary reflected Gray code representation.
|
|
1
|
|
|
0, 6, 18, 90, 330, 1386, 5418, 21930, 87210, 349866, 1397418, 5593770, 22366890, 89483946, 357903018, 1431677610, 5726579370, 22906579626, 91625794218, 366504225450, 1466014804650, 5864063412906, 23456245263018, 93824997829290, 375299957762730, 1501199898159786, 6004799458421418
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
Cyclops palindromic numbers in base 2 are numbers with middle bit 0, having equal number of 1's on both side of the 0. There is a single 0 bit in the middle and the total number of bits is odd. The middle '0' represents the eye of a cyclops.
a(n) mod 6 = 0.
|
|
LINKS
|
|
|
FORMULA
|
a(n) = (-2*(1+((-2)^n)-(2^(2*n+1))))/3.
|
|
EXAMPLE
|
90 is in the sequence because the binary reflected Gray code representation of 90 is '1110111' which is a cyclops palindromic binary number.
|
|
PROG
|
(Python)
def a(n):
....return (-2*(1+((-2)**n)-(2**(2*n+1))))/3
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|