OFFSET
1,1
COMMENTS
Let d(1..k) be the digits in the number and let i = 1. If d(i) is odd set i = i+d(i)+1 else i = i-d(i)-1. The number is a term if i reaches k+1.
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..10000
FORMULA
Numbers must start with 1, 3, 5, 7, 9 and end with 0, 2, 4, 6, 8.
Let eSum = Sum_{i=1..k, d(i) is even} d(i)+1, and oSum = Sum_{i=1..k, d(i) is odd} d(i)+1. Then eSum-oSum+k = 0.
EXAMPLE
For 33000 the digit positions visited are 1, 5, 4, 3, 2, 6(outside to the right) so 33000 is a term.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Lars Blomberg and Eric Angelini, Apr 25 2017
STATUS
approved