A363872 - OEIS

A363872

Lexicographically earliest sequence of distinct terms > 0 such that n is a substring of a(n) + a(n+1).

1, 9, 3, 10, 4, 11, 5, 2, 6, 13, 87, 23, 89, 24, 90, 25, 91, 26, 92, 27, 93, 28, 94, 29, 95, 30, 96, 31, 97, 32, 98, 33, 99, 34, 100, 35, 101, 36, 102, 37, 103, 38, 104, 39, 105, 40, 106, 41, 7, 42, 8, 43, 109, 44, 110, 45, 111, 46, 12, 47, 113, 48, 14, 49, 15

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..65.

Eric Angelini, Échecs et Maths, Personal blog, bottom of page.

EXAMPLE

n = 1 is a substring of the sum 1 + 9 = 10

n = 2 is a substring of the sum 9 + 3 = 12

n = 3 is a substring of the sum 3 + 10 = 13

n = 4 is a substring of the sum 10 + 4 = 14

n = 5 is a substring of the sum 4 + 11 = 15

n = 6 is a substring of the sum 11 + 5 = 16

...

n = 10 is a substring of the sum 13 + 87 = 100, etc.

MAPLE

R:= 1: x:= 1: S:= {1}:

for n from 1 to 100 do

ns:= convert(n, string);

for y from 1 do

if member(y, S) then next fi;

if SearchText(ns, convert(x+y, string)) <> 0 then

R:= R, y; x:= y; S:= S union {y}; break

od:

R; # Robert Israel, Jul 04 2023

MATHEMATICA

a[1] = 1; a[n_] := a[n] = Module[{k = 2}, While[! FreeQ[Array[a, n - 1], k] || ! StringContainsQ[ToString[a[n - 1] + k], ToString[n - 1]], k++]; k]; Array[a, 100] (* Amiram Eldar, Jul 04 2023 *)

CROSSREFS

Cf. A299952.

Sequence in context: A361062 A003565 A238105 * A166203 A248312 A329653

Adjacent sequences: A363869 A363870 A363871 * A363873 A363874 A363875

KEYWORD

base,nonn

AUTHOR

Eric Angelini, Jul 03 2023

STATUS

approved