A354710 Records in A009101.

0, 102, 110, 140, 150, 170, 209, 210, 260, 330, 4506, 11620, 17054, 19008, 20979, 24120, 27780, 32305, 32805, 34590, 42012, 52054, 55048, 59049, 65610, 70536, 75006, 90432, 111006, 112050, 118098, 120594, 136052, 150297, 153302, 160824, 181039, 183708, 208044

Offset

0,2

Links

Table of n, a(n) for n=0..38.

Prog

(Python)
import numpy
input_list = []
output_list = []
max_list = []
range_ = 10 ** 7
lower = 0
upper = lower + range_
for i in range(lower, upper):
    input_list.append(i)
    number = str(i)
    results_list = []
    total = 0
    total_list = []
    while True:
        number_list = []
        for x in list(number):
            number_list.append(int(x))
        results_list.append(numpy.prod(number_list))
        total += numpy.prod(number_list)
        if total in total_list:
            output_list.append(total_list[-1])
            if total_list[-1] >= max(output_list):
                if total_list[-1] not in max_list:
                    max_list.append(total_list[-1])
            break
        total_list.append(total)
        number = str(total)
print(max_list)
(Python)
from math import prod
from itertools import count, islice
def pd(n): return prod(map(int, str(n)))
def f(x): return x + pd(x)
def agen(): # generator of terms
    record, seen = -1, set()
    for n in count(0):
        x = pd(n)
        if x in seen: continue
        seen.add(x)
        fx = f(x)
        while x != fx: x, fx = fx, f(fx)
        if fx > record:
            record = fx
            yield record
print(list(islice(agen(), 39))) # Michael S. Branicky, Jun 21 2022

Crossrefs

Cf. A009101.

Sequence in context: A046293 A241179 A096924 * A031413 A127665 A097037

Adjacent sequences: A354707 A354708 A354709 * A354711 A354712 A354713

Keyword

base,nonn

Author

Marc-Thomas Russo, Jun 03 2022

Status

approved