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.
%I A367070 #28 Mar 25 2024 12:05:45
%S A367070 1,16,128,250,480,864,21600,62208,73728
%N A367070 Numbers k such that k = (product of nonzero digits) * (sum of digits) for the digits of k in base 7.
%C A367070 There is a finite number of such numbers; we only calculated the terms in [1, 10^10] (Property 1' of Clerc).
%H A367070 René-Louis Clerc, <a href="https://hal.science/hal-04235744">Quelques nombres de Niven-Harshad particuliers</a>, 2023.
%H A367070 René-Louis Clerc, <a href="https://ut3-toulouseinp.hal.science/hal-04507547">Nombres S+P, maxSP, minSP et |P-S|</a>, hal-04507547 [math.nt], 2024. (In French)
%e A367070 21600 = 116655_7, (1+1+6+6+5+5)*(1*1*6*6*5*5) = 24*900 = 21600.
%t A367070 Select[Range[7^7], #1 == Times @@ DeleteCases[#2, 0]*Total[#2] & @@ {#, IntegerDigits[#, 7]} &] (* _Michael De Vlieger_, Mar 25 2024 *)
%o A367070 (PARI) isok(k, b) = my(d=select(x->(x>0), digits(k,b))); vecprod(d)*vecsum(d) == k;
%o A367070 for (k=1, 10^5, if (isok(k, 7), print1(k, ", ")))
%Y A367070 Cf. A066282, A062331, A023651, A038364, A038369, A062237.
%K A367070 base,nonn,fini,more
%O A367070 1,2
%A A367070 _René-Louis Clerc_, Jan 10 2024