A347024 There are a(n) digits between a(n) and the next copy of the string a(n) read backwards. This is the lexicographically earliest sequence of distinct positive terms with this property.

1, 2, 10, 20, 3, 4, 7, 8, 30, 400, 17, 5, 80, 9, 6, 15, 100, 26, 19, 11, 27, 16, 18, 51, 40, 31, 12, 21, 29, 13, 61, 62, 81, 210, 72, 22, 310, 41, 23, 28, 71, 34, 49, 200, 46, 33, 220, 91, 50, 53, 24, 60, 83, 820, 35, 25, 37, 143, 116, 32, 633, 42, 1000, 194, 64, 45, 270, 218, 65, 305, 117, 352, 36, 14

Offset

1,2

Links

Table of n, a(n) for n=1..74.

Example

a(1) = 1; there is 1 digit between a(1) and the "1" of 10: this is the digit 2;
a(2) = 2; there are 2 digits between a(2) and the "2" of 20: they are 1 and 0;
a(3) = 10; there are 10 digits between a(3) and the next string "01" (formed by the terms "400, 17"): they are 2, 0, 3, 4, 7, 8, 3, 0, 4 and 0;
a(4) = 20; there are 20 digits between a(4) and the next string "02" (formed by the terms "100, 26"): they are 3, 4, 7, 8, 3, 0, 4, 0, 0, 1, 7, 5, 8, 0, 9, 6, 1, 5, 1 and 0;
a(5) = 3; there are 3 digits between a(5) and the "3" of 30: they are 4, 7 and 8;
a(6) = 4; there are 4 digits between a(6) and the "4" of 400: they are 7, 8, 3 and 0;
a(7) = 7; there are 7 digits between a(7) and the "7" of 17: they are 8, 3, 0, 4, 0, 0 and 1; etc.

Crossrefs

Cf. A346810, A303151.

Sequence in context: A342543 A342539 A346810 * A009342 A357486 A350508

Adjacent sequences: A347021 A347022 A347023 * A347025 A347026 A347027

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Aug 11 2021

Status

approved