A347347 If n is odd, a(n) is the smallest positive integer that is a palindrome when represented in binary, and is made by appending some number (zero or more) of binary digits on the left of n's binary representation. If n is even, then a(n) = 0.
1, 0, 3, 0, 5, 0, 7, 0, 9, 0, 27, 0, 45, 0, 15, 0, 17, 0, 51, 0, 21, 0, 119, 0, 153, 0, 27, 0, 93, 0, 31, 0, 33, 0, 99, 0, 165, 0, 231, 0, 297, 0, 107, 0, 45, 0, 495, 0, 561, 0, 51, 0, 693, 0, 119, 0, 313, 0, 443, 0, 189, 0, 63, 0, 65, 0, 195, 0, 325, 0, 455, 0
Offset: 1
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..10000
Programs
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Python
def A347347(n): if n % 2 == 0: return 0 s = bin(n)[2:] if s == s[::-1]: return n for i in range(1,len(s)): if s[:-i]== s[-i-1::-1]: return int(s[:-i-1:-1]+s,2)
Comments