A354885 Numbers that are palindromes in both ternary and balanced ternary representations.
0, 1, 4, 10, 13, 16, 28, 40, 52, 82, 91, 112, 121, 160, 244, 280, 328, 364, 484, 730, 757, 820, 847, 976, 1003, 1066, 1093, 1312, 1456, 2188, 2296, 2440, 2548, 2920, 3028, 3172, 3280, 3904, 4372, 6562, 6643, 6832, 6913, 7300, 7381, 7570, 7651, 8752, 8833, 9022
Offset: 1
Examples
4 is a term since its ternary and balanced ternary representation are both 11 which is a palindrome. 16 is a term since its ternary representation is 121 and its balanced ternary representation (with 2 standing for the -1 digit) is 1221, and both are palindromes.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Crossrefs
Programs
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Mathematica
Select[Range[0, 10^4], PalindromeQ[IntegerDigits[#, 3]] && PalindromeQ @ balTernDigits[#] &] (* using balTernDigits by Robert G. Wilson v at A134027 *)
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PARI
is(n) = {my (t=digits(n,3)); if (t==Vecrev(t), my (b=[], d); while (n, b=concat(d=[0,1,-1][1+n%3], b); n=(n-d)/3); b==Vecrev(b), 0)} \\ Rémy Sigrist, Jun 10 2022