A354719 Replace each even digit in n with the digit to its left.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 11, 11, 13, 11, 15, 11, 17, 11, 19, 2, 11, 22, 33, 42, 55, 62, 77, 82, 99, 33, 31, 33, 33, 33, 35, 33, 37, 33, 39, 4, 11, 24, 33, 44, 55, 64, 77, 84, 99, 55, 51, 55, 53, 55, 55, 55, 57, 55, 59, 6, 11, 26, 33, 46, 55, 66, 77

Offset

0,3

Comments

If the leftmost digit in n is even, wrap around and replace it with the rightmost digit in n (see example).

Links

Michael De Vlieger, Table of n, a(n) for n = 0..10000

Gavin Lupo, Logarithmic scatterplot of (n, a(n)) for n = 1..10000

Example

n    =  4 2 7 8 1
        ^ ^   ^      even digits,
a(n) =  1 4 7 7 1    to their left in n

Mathematica

Array[FromDigits@ Map[If[EvenQ@ #1, #2, #1] & @@ # &, Transpose@ {#, RotateRight[#, 1]}] &@ IntegerDigits[#] &, 67] (* Michael De Vlieger, Jun 19 2022 *)

Prog

(Python)
def a(n):
    digits = list(map(int, str(n)))
    out = (d if d%2 else digits[i-1] for i, d in enumerate(digits))
    return int("".join(map(str, out)))
print([a(n) for n in range(68)]) # Michael S. Branicky, Jun 04 2022
(PARI) prec(d, k) = k--; if (! k, k = #d); k;
a(n) = my(d=digits(n), v=d); for (k=1, #d, if (!(d[k] % 2), v[k] = d[prec(d, k)])); fromdigits(v); \\ Michel Marcus, Jun 04 2022

Crossrefs

Cf. A139337, A348179, A349422.

Sequence in context: A338830 A262037 A262039 * A340835 A123241 A355222

Adjacent sequences: A354716 A354717 A354718 * A354720 A354721 A354722

Keyword

nonn,base,easy,look,hear

Author

Gavin Lupo, Jun 03 2022

Status

approved