A334737 Lexicographically earliest sequence of distinct positive integers such that the digital root of a(n+1) divides a(n).

1, 10, 2, 11, 19, 28, 4, 13, 37, 46, 20, 5, 14, 7, 16, 8, 17, 55, 23, 64, 22, 29, 73, 82, 38, 47, 91, 25, 32, 26, 56, 31, 100, 40, 35, 34, 65, 41, 109, 118, 74, 83, 127, 136, 44, 49, 43, 145, 50, 59, 154, 52, 58, 92, 67, 163, 172, 76, 85, 68, 94, 101, 181, 190, 77, 61, 199

Offset: 1

Author

Eric Angelini and Carole Dubois, May 09 2020

Keywords

• base
• nonn

Examples

			a(1) = 1 is divisible by the digital root of 10 (which is 1 + 0 = 1);
a(2) = 10 is divisible by the dig. root of 2 (which is = 2);
a(3) = 2 is divisible by the dig. root of 11 (which is 1 + 1 = 2);
a(4) = 11 is divisible by the dig. root of 19 (which is 1 + 9 = 10 => 1 + 0 = 1);
a(5) = 19 is divisible by the dig. root of 28 (which is 2 + 8 = 10 => 1 + 0 = 1);
a(6) = 28 is divisible by the dig. root of 4 (which is = 4); etc.
		

Links

• Carole Dubois, Table of n, a(n) for n = 1..5005

Crossrefs

Cf. A248025, A334837 (same idea, but digital sum instead of digital root in the Name section).