OFFSET
1,3
EXAMPLE
a(1) = 1 (given).
a(2) = 0 (number of distinct prime divisors of 1).
a(3) = 2 (number of distinct prime divisors of 10); etc.
MATHEMATICA
l = {1}; s = "1"; Do[k = ToExpression[s]; m = Length[FactorInteger[k]]; AppendTo[l, m]; s = s <> ToString[m], {n, 1, 100}]; Print[l] (* Ryan Propper, Oct 10 2005 *)
PROG
(Python)
from sympy import factorint
def aupton(terms):
alst, astr = [1], "1"
for n in range(2, terms+1):
an = len(factorint(int(astr)))
alst.append(an)
astr += str(an)
return alst
print(aupton(45)) # Michael S. Branicky, Dec 02 2021
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Aug 11 2005
EXTENSIONS
More terms from Ryan Propper, Oct 10 2005
Definition corrected by N. J. A. Sloane, Oct 14 2020 at the suggestion of David James Sycamore
a(71)-a(85) from Michael S. Branicky, Dec 02 2021
STATUS
approved