A354710 - OEIS

%I #17 Sep 06 2022 15:09:04

%S 0,102,110,140,150,170,209,210,260,330,4506,11620,17054,19008,20979,

%T 24120,27780,32305,32805,34590,42012,52054,55048,59049,65610,70536,

%U 75006,90432,111006,112050,118098,120594,136052,150297,153302,160824,181039,183708,208044

%N Records in A009101.

%o (Python)

%o import numpy

%o input_list = []

%o output_list = []

%o max_list = []

%o range_ = 10 ** 7

%o lower = 0

%o upper = lower + range_

%o for i in range(lower, upper):

%o     input_list.append(i)

%o     number = str(i)

%o     results_list = []

%o     total = 0

%o     total_list = []

%o     while True:

%o         number_list = []

%o         for x in list(number):

%o             number_list.append(int(x))

%o         results_list.append(numpy.prod(number_list))

%o         total += numpy.prod(number_list)

%o         if total in total_list:

%o             output_list.append(total_list[-1])

%o             if total_list[-1] >= max(output_list):

%o                 if total_list[-1] not in max_list:

%o                     max_list.append(total_list[-1])

%o             break

%o         total_list.append(total)

%o         number = str(total)

%o print(max_list)

%o (Python)

%o from math import prod

%o from itertools import count, islice

%o def pd(n): return prod(map(int, str(n)))

%o def f(x): return x + pd(x)

%o def agen(): # generator of terms

%o     record, seen = -1, set()

%o     for n in count(0):

%o         x = pd(n)

%o         if x in seen: continue

%o         seen.add(x)

%o         fx = f(x)

%o         while x != fx: x, fx = fx, f(fx)

%o         if fx > record:

%o             record = fx

%o             yield record

%o print(list(islice(agen(), 39))) # _Michael S. Branicky_, Jun 21 2022

%Y Cf. A009101.

%K base,nonn

%O 0,2

%A _Marc-Thomas Russo_, Jun 03 2022