OFFSET
1,2
COMMENTS
Any number > 9 consisting of just one digit (A014181) can't be in the list. (Provable using the Carmichael function.)
EXAMPLE
24 = 4^2 + 2^3 is a term.
332 = 2^3 + 3^4 + 3^5 is another term.
PROG
(Python)
liste = []
for ex in range(0, 20):
for t in range(1, 10000):
n = t
pot = ex
ergebnis = 0
while n > 0:
pot = pot + 1
rest = n % 10
n = (n - rest) // 10
zw = 1
for i in range(pot):
zw = zw * rest
ergebnis = ergebnis + zw
if (int(ergebnis) == t) and (t not in liste):
liste.append(t)
liste.sort()
print(liste)
(Python)
def powsum(digits, startexp):
return sum(digits[i]**(startexp+i) for i in range(len(digits)))
def ok(n):
if n < 10: return True
s = str(n)
if set(s) <= {'0', '1'}: return False
digits, startexp = list(map(int, s))[::-1], 1
while powsum(digits, startexp) < n: startexp += 1
return n == powsum(digits, startexp)
print(list(filter(ok, range(2*10**5)))) # Michael S. Branicky, Aug 29 2021
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Reiner Moewald, Aug 21 2021
EXTENSIONS
a(15)-a(19) from Michael S. Branicky, Aug 31 2021
STATUS
approved