|
Search: id:A048703
|
|
|
| A048703 |
|
Number of quaternary (base 4) palindromes of even length. |
|
+0
3
|
|
| 0, 5, 10, 15, 65, 85, 105, 125, 130, 150, 170, 190, 195, 215, 235, 255, 1025, 1105, 1185, 1265, 1285, 1365, 1445, 1525, 1545, 1625, 1705, 1785, 1805, 1885, 1965, 2045, 2050, 2130, 2210, 2290, 2310, 2390
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
FORMULA
|
a(n) = (2^(floor_log_2_coarse(n)+1))*n + sum('(bit_i(n, i+((-1)^i))*(2^(floor_log_2_coarse(n)-i)))', 'i'=0..floor_log_2_coarse(n));
|
|
MAPLE
|
bit_i := (x, i) -> `mod`(floor(x/(2^i)), 2); # (Like floor_log_2 but even results are incremented by one)
floor_log_2_coarse := proc(n) local nn, i: nn := n; for i from -1 to n do if(0 = nn) then RETURN(i+(1-(i mod 2))); fi: nn := floor(nn/2); od: end:
|
|
CROSSREFS
|
A048704 this sequence divided by 5, A048701 binary palindromes of even length, A014192 palindromes in base 4 (also of odd lengths)
Sequence in context: A138521 A022600 A067237 this_sequence A020332 A044830 A033002
Adjacent sequences: A048700 A048701 A048702 this_sequence A048704 A048705 A048706
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Antti Karttunen, Mar 07 1999
|
|
|
Search completed in 0.002 seconds
|
