OFFSET
1,2
EXAMPLE
a(10) = 11 starts with 1, which is the product 1*1;
a(20) = 126 starts with 12, which is the product 1*2*6;
a(42) = 1755 starts with 175, which is the product ; 1*7*5*5; etc.
MATHEMATICA
q[n_] := Module[{d = IntegerDigits[n], p, dp, ndp}, p = Times @@ d; dp = IntegerDigits[p]; ndp = Length[dp]; dp == d[[1 ;; ndp]]]; Select[Range[12000], q] (* Amiram Eldar, Mar 18 2022 *)
PROG
(Python)
from math import prod
def ok(n): s = str(n); return s.startswith(str(prod(map(int, s))))
print([k for k in range(1, 12000) if ok(k)]) # Michael S. Branicky, Mar 17 2022
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Eric Angelini and Carole Dubois, Mar 17 2022
STATUS
approved