A319724 Write n in 7-ary, sort digits into decreasing order.

0, 1, 2, 3, 4, 5, 6, 7, 8, 15, 22, 29, 36, 43, 14, 15, 16, 23, 30, 37, 44, 21, 22, 23, 24, 31, 38, 45, 28, 29, 30, 31, 32, 39, 46, 35, 36, 37, 38, 39, 40, 47, 42, 43, 44, 45, 46, 47, 48, 49, 56, 105, 154, 203, 252, 301, 56, 57, 106, 155, 204, 253, 302, 105, 106, 113, 162

Offset

0,3

Links

Seiichi Manyama, Table of n, a(n) for n = 0..2400

Formula

n <= a(n) < 7n. - Charles R Greathouse IV, Aug 07 2024

Mathematica

Table[FromDigits[ReverseSort[IntegerDigits[n, 7]], 7], {n, 0, 100}] (* Paolo Xausa, Aug 07 2024 *)

Prog

(Ruby)
def A(k, n)
  (0..n).map{|i| i.to_s(k).split('').sort.reverse.join.to_i(k)}
end
p A(7, 100)
(PARI) a(n) = fromdigits(vecsort(digits(n, 7), , 4), 7); \\ Michel Marcus, Sep 26 2018

Crossrefs

b-ary: A073138 (b=2), A319651 (b=3), A319720 (b=4), A319722 (b=5), A319723 (b=6), this sequence (b=7), A319725 (b=8), A319726 (b=9), A004186 (b=10).

Cf. A165071, A319655.

Sequence in context: A245802 A085904 A032997 * A097546 A004837 A032863

Adjacent sequences: A319721 A319722 A319723 * A319725 A319726 A319727

Keyword

nonn,base,look,easy,changed

Author

Seiichi Manyama, Sep 26 2018

Status

approved