A229527 Start with 1, skip (sum of digits of n) numbers, accept next number.

1, 3, 7, 15, 22, 27, 37, 48, 61, 69, 85, 99, 118, 129, 142, 150, 157, 171, 181, 192, 205, 213, 220, 225, 235, 246, 259, 276, 292, 306, 316, 327, 340, 348, 364, 378, 397, 417, 430, 438, 454, 468, 487, 507, 520, 528, 544, 558, 577, 597

Offset: 1

Author

Dave Durgin, Sep 25 2013

Keywords

• nonn
• base

Examples

			a(1)=1, a(2)=1+1+1=3, a(3)=3+3+1=7, a(4)=7+7+1=15, a(5)=15+1+5+1=22, a(6)=22+2+2+1=27, ...
		

Links

• Robert G. Wilson v, Table of n, a(n) for n = 1..10000
• Index entries for Colombian or self numbers and related sequences

Crossrefs

Cf. A007953, A007612, A004207, A160939.

Programs

Mathematica

a[n_] := a[n] = a[n - 1] + 1 + Plus @@ IntegerDigits@a[n - 1]; a[1] = 1; Array[a, 50] (* Robert G. Wilson v, Aug 01 2018 *)

Python

from itertools import islice
def A229527_gen(): # generator of terms
    a = 1
    while True:
        yield a
        a += sum(map(int,str(a)))+1
A229527_list = list(islice(A229527_gen(),40)) # Chai Wah Wu, Aug 09 2025

Formula

a(n+1) = a(n) + (sum of digits of a(n)) + 1.