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 A085890 #19 Sep 19 2024 14:42:08 %S A085890 1,2,3,4,5,6,7,8,9,10,21,32,54,98,210,432 %N A085890 7-smooth numbers (A002473) using digits in descending order. Zero is followed by a 9. %C A085890 No more terms < 10^1000. Probably no more terms. - _David Wasserman_, Feb 10 2005 %e A085890 432 is a member as 432= 2^4*3^3. %o A085890 (PARI) hcn(n) = while (!(n%2), n \=2); while (!(n%3), n \=3); while (!(n%5), n \=5); while (!(n%7), n \=7); n == 1; %o A085890 for (i = 0, 1000, for (j = 1, 9, my(n = sum(k = j - i, j, (k%10)*10^(i - j + k))); if (hcn(n), print1(n, ", ")))); /* _David Wasserman_, Feb 10 2005 */ %Y A085890 Intersection of A002473 and A158699. %Y A085890 Cf. A085889. %K A085890 base,nonn %O A085890 1,2 %A A085890 _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jul 10 2003 %E A085890 More terms from _David Wasserman_, Feb 10 2005