A363079 The sum of the digits present in a(n) and a(n+1) divides exactly a(n). This is the lexicographically earliest infinite sequence of distinct positive terms having this property.

10, 13, 18, 27, 99, 69, 17, 36, 12, 21, 22, 16, 45, 15, 54, 63, 39, 999, 19, 72, 30, 25, 189, 81, 198, 31, 1899, 499999999999999999999

Offset

1,1

Comments

If we want the sequence to be infinite, we cannot extend it with terms < 10. After a(28) = 499999999999999999999 the terms become exponentially huge and impossible to present here.

Links

Table of n, a(n) for n=1..28.

Eric Angelini, SuperSums, SuperProducts, personal blog.

Example

digitsum a(1) + digitsum a(2) = 1 + 0 + 1 + 3 = 5 and 5 divides exactly a(1) = 10;
digitsum a(2) + digitsum a(3) = 1 + 3 + 1 + 8 = 13 and 13 divides exactly a(2) = 13;
digitsum a(3) + digitsum a(4) = 1 + 8 + 2 + 7 = 18 and 18 divides exactly a(3) = 18;
digitsum a(4) + digitsum a(5) = 2 + 7 + 9 + 9 = 27 and 27 divides exactly a(4) = 27;
digitsum a(5) + digitsum a(6) = 9 + 9 + 6 + 9 = 33 and 33 divides exactly a(5) = 99; etc.

Crossrefs

Cf. A364120, A364187, A364188.

Sequence in context: A081642 A174274 A120155 * A159839 A129075 A095918

Adjacent sequences: A363076 A363077 A363078 * A363080 A363081 A363082

Keyword

base,nonn

Author

Eric Angelini, Jul 13 2023

Status

approved