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 A384632 #13 Jun 17 2025 18:00:47 %S A384632 0,1,2,3,4,6,12,5,7,16,24,8,18,9,10,30,11,36,48,13,14,15,17,19,20,21, %T A384632 28,22,40,23,25,26,27,29,32,31,42,33,60,34,35,37,38,39,54,41,43,44,45, %U A384632 46,49,47,50,51,52,53,56,55,72,57,58,62,59,63,61,64,65 %N A384632 a(0)=0. For each digit d in the sequence, let a(n) equal the smallest unused integer which has at least d divisors. %e A384632 a(0) = 0. %e A384632 a(1) = Smallest unused integer with at least 0 divisors = 1. %e A384632 a(2) = Smallest unused integer with at least 1 divisor = 2. %e A384632 a(3) = Smallest unused integer with at least 2 divisors = 3. %e A384632 a(4) = Smallest unused integer with at least 3 divisors = 4. %e A384632 a(5) = Smallest unused integer with at least 4 divisors = 6. %e A384632 a(6) = Smallest unused integer with at least 6 divisors = 12. %e A384632 a(7) = Smallest unused integer with at least 1 divisor = 5. %e A384632 a(8) = Smallest unused integer with at least 2 divisors = 7. %o A384632 (Python) %o A384632 from sympy import divisor_count %o A384632 a = [0] %o A384632 for n in range(100): %o A384632 if a[n] >= 10: %o A384632 split = [int(d) for d in str(a[n])] %o A384632 else: %o A384632 split = [a[n]] %o A384632 for s in split: %o A384632 num = 1 %o A384632 while True: %o A384632 if divisor_count(num) >= s and num not in a: %o A384632 a.append(num) %o A384632 break %o A384632 num += 1 %o A384632 print(a) %Y A384632 Cf. A000005, A362371, A362551. %K A384632 nonn,base %O A384632 0,3 %A A384632 _Gavin Lupo_, Jun 05 2025