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.

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, 25, 42, 59, 29, 29, 46, 63, 34, 34, 34, 51, 38, 38, 38, 55, 42, 42, 42, 59, 46, 46, 46, 63, 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

Offset

0,3

Links

Jonathan Frech, Table of n, a(n) for n = 0..10000

Prog

(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); ); }
a(n) = {my(dn = digits(n, 4), m = n); while (!isok(m, dn), m++); m; } \\ Michel Marcus, Apr 07 2021

Crossrefs

Sequences related to palindromic floor and ceiling: A175298, A206913, A206914, A261423, A262038, and the large block of consecutive sequences beginning at A265509.

Sequence in context: A140312 A088887 A368085 * A066911 A326229 A326187

Adjacent sequences: A265543 A265544 A265545 * A265547 A265548 A265549

Keyword

nonn,base

Author

N. J. A. Sloane, Dec 10 2015

Status

approved