A387867 a(n) is the number of n-digit terms in A387866.

0, 9, 46, 503, 6252, 84201, 1105270, 14040589, 172462528, 2059008115

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Mathematica

a[n_]:=Module[{c=0}, For[h=10^(n-1), h<10^n, h++, If[Sum[Boole[Product[Part[(digits=IntegerDigits[h]), i], {i, k}] == Product[Part[digits, i], {i, k+1, n}]], {k, n-1}]>0, c++]]; c]; Array[a, 5]

Prog

(Python)
from math import prod
terms = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
def ok(n):
 d = list(map(int, str(n)))
 return any(prod(d[:i]) == prod(d[i:]) for i in range(1, len(d)))
start = 1
while 0 in terms[1:]:
  if ok(start):
     terms[len(str(start))-1] += 1
  start += 1
print(terms)
# David Consiglio, Jr., Sep 19 2025

Crossrefs

Cf. A387866.

Sequence in context: A054140 A370622 A307955 * A110675 A265805 A274270

Adjacent sequences: A387864 A387865 A387866 * A387868 A387869 A387870

Keyword

nonn,base,more

Author

Stefano Spezia, Sep 10 2025

Extensions

a(10) from David Consiglio, Jr., Sep 19 2025

Status

approved