cp's OEIS Frontend

A265546 a(n) = smallest base-4 palindrome m >= n such that every base-4 digit of n is <= the corresponding base-4 digit of m; m is written in base 10.

%I A265546 #13 Apr 07 2021 14:23:18
%S A265546 0,1,2,3,5,5,10,15,10,10,10,15,15,15,15,15,17,17,34,51,21,21,38,55,25,
%T A265546 25,42,59,29,29,46,63,34,34,34,51,38,38,38,55,42,42,42,59,46,46,46,63,
%U A265546 51,51,51,51,55,55,55,55,59,59,59,59,63,63,63,63,65,65,130,195,85,85,150,215,105,105,170,235,125,125,190
%N A265546 a(n) = smallest base-4 palindrome m >= n such that every base-4 digit of n is <= the corresponding base-4 digit of m; m is written in base 10.
%H A265546 Jonathan Frech, <a href="/A265546/b265546.txt">Table of n, a(n) for n = 0..10000</a>
%o A265546 (PARI) isok(m, dn) = {my(dm = digits(m, 4)); if ((Vecrev(dm) == dm) && (#dm == #dn), for (i=1, #dn, if (dn[i] > dm[i], return (0))); return(1););}
%o A265546 a(n) = {my(dn = digits(n, 4), m = n); while (!isok(m, dn), m++); m;} \\ _Michel Marcus_, Apr 07 2021
%Y A265546 Sequences related to palindromic floor and ceiling: A175298, A206913, A206914, A261423, A262038, and the large block of consecutive sequences beginning at A265509.
%K A265546 nonn,base
%O A265546 0,3
%A A265546 _N. J. A. Sloane_, Dec 10 2015