login
A272670
Numbers whose binary expansion is not palindromic but which when reversed and leading zeros omitted, does form a palindrome.
3
2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24, 28, 30, 32, 34, 36, 40, 42, 48, 54, 56, 60, 62, 64, 66, 68, 72, 80, 84, 90, 96, 102, 108, 112, 120, 124, 126, 128, 130, 132, 136, 144, 146, 160, 168, 170, 180, 186, 192, 198, 204, 214, 216, 224, 238, 240, 248, 252, 254
OFFSET
1,1
COMMENTS
Decimal interpretation of A273245. Twice A057890.
MAPLE
isPal := proc(L::list)
local i;
for i from 1 to nops(L)/2 do
if op(i, L) <> op(-i, L) then
return false;
end if;
end do:
true ;
end proc:
isA272670 := proc(n)
local bdgs ;
bdgs := convert(n, base, 2) ;
if isPal(bdgs) then
return false;
else
A000265(n) ;
bdgs := convert(%, base, 2) ;
isPal(bdgs) ;
end if;
end proc:
for n from 1 to 500 do
if isA272670(n) then
printf("%d, ", n) ;
end if;
end do: # R. J. Mathar, May 20 2016
PROG
(Python)
A272670_list = [n for n in range(1, 10**4) if bin(n)[2:] != bin(n)[:1:-1] and bin(n)[2:].rstrip('0') == bin(n)[:1:-1].lstrip('0')] # Chai Wah Wu, May 21 2016
CROSSREFS
Cf. A006995, A057890, A273245, A273329, subsequence of A154809.
Sequence in context: A029741 A240171 A221284 * A234521 A085125 A251237
KEYWORD
nonn,base,easy
AUTHOR
N. J. A. Sloane, May 19 2016
STATUS
approved