OFFSET
1,1
COMMENTS
All the terms end with 9 (A017377).
LINKS
Stefano Spezia, Table of n, a(n) for n = 1..10000
FORMULA
Limit_{n->oo} a(n)/a(n-1) = 1.
EXAMPLE
9 = 3*3, 39 = 3*13, 69 = 3*23, 99 = 3*33, 129 = 3*43, 159 = 3*53, 169 = 13*13, 189 = 3*63, ...
MATHEMATICA
a={}; For[n=0, n<=250, n++, For[k=0, k<=n, k++, If[Mod[10*n+9, 10*k+3]==0 && Mod[(10*n+9)/(10*k+3), 10]==3&& 10*n+9>Max[a], AppendTo[a, 10*n+9]]]]; a
PROG
(Python)
def aupto(lim): return sorted(set(a*b for a in range(3, lim//3+1, 10) for b in range(a, lim//a+1, 10)))
print(aupto(1270)) # Michael S. Branicky, Aug 08 2021
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Stefano Spezia, Aug 08 2021
STATUS
approved