cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A352742 a(n) is the smallest number > 1 that is not divisible by 10 but is divisible by the n-th power of the sum of its digits.

This page as a plain text file.
%I A352742 #54 Apr 05 2022 21:12:15
%S A352742 2,81,512,2401,11101212,34012224,612220032,20047612231936,
%T A352742 3904305912313344,7800803212802061312,1025300207121086650406,
%U A352742 213780015477322248820322,14076019706120526112710656,2670419511272061205254504361,2759031540715333904109053133443,10530400808911150200350000010411
%N A352742 a(n) is the smallest number > 1 that is not divisible by 10 but is divisible by the n-th power of the sum of its digits.
%C A352742 a(n+1) >= a(n).
%C A352742 When A072408(n) is not multiple of 10 then a(n) <= A072408(n).
%C A352742 a(n) = m * k^n where m is a positive integer and k is the sum of digits of a(n).
%C A352742 Conjecture: No term is a multiple of 5.
%C A352742 a(28) = 265^28, disproving the above conjecture. - _Charles R Greathouse IV_, Apr 02 2022
%e A352742 For n=5, 11101212 is not divisible by 10 but is divisible by the 5th power of the sum of its digits, that being (1+1+1+0+1+2+1+2)^5 = 9^5. There is no smaller such number.
%Y A352742 Cf. A072408.
%K A352742 nonn,base
%O A352742 1,1
%A A352742 _Nicolas Bělohoubek_, Mar 31 2022
%E A352742 a(7)-a(8) confirmed by _Jon E. Schoenfield_, Mar 31 2022
%E A352742 a(9)-a(16) from _Charles R Greathouse IV_, Apr 02 2022