

A216589


Numbers n which don't have a preimage for A216556, i.e., such that A216587(n)=1.


3



0, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

Concretely, numbers having "20", "30", ..., "90" or "00" as a substring, or starting with "11", "12", ... "19", and the number 0.
Note that A216557 does not necessarily yield 0 for these numbers, e.g., 10 has no preimage for A216556, but 210 does have, and 10 > 21 > ... > 98 > 109.


LINKS



FORMULA

A216587(n)=1 if and only if n is in this sequence.


PROG

(PARI) is_A216589(n)={n  return(1); n=Vec(Str(n)); n[1]<"2" & 1<#n & n[2]>"0" & return(1); for(i=2, #n, n[i]=="0"  next; n[i1]=="1"  return(1))}


CROSSREFS



KEYWORD

nonn,base,easy


AUTHOR



STATUS

approved



