OFFSET
1,2
COMMENTS
In the definition of the sequence, consider the number of occurrences of string s in string t to be the number of positions within t that have a perfect match with the digits in s. Thus the number of occurrences of 11 in 1111 is 3 and not 2.
LINKS
John Mason, Table of n, a(n) for n = 1..10000
EXAMPLE
a(12) is 1 as there is one occurrence of "12" in the string formed by concatenating a(1) through a(11).
MATHEMATICA
FromDigits /@ Nest[Function[{a, n}, Append[a, If[# == 0, IntegerDigits@ n, IntegerDigits@ #] &@ SequenceCount[Join @@ a, IntegerDigits@ n]]] @@ {#, Length@ # + 1} &, {{1}}, 67] (* Michael De Vlieger, Nov 26 2018 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
John Mason, Nov 26 2018
STATUS
approved