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 A387025 #7 Aug 18 2025 16:16:14
%S A387025 1,2,3,2,5,1,7,8,9,2,11,6,13,2,15,1,17,2,19,10,21,2,23,2,25,1,27,28,
%T A387025 29,2,31,16,33,2,35,18,37,2,39,2,41,1,43,44,45,2,47,3,49,1,17,52,53,2,
%U A387025 55,1,57,2,59,30,61,2,63,32,65,2,67,2,69,1,71,4,73,2
%N A387025 Start with the list of positive integers L_1 = (1, 2, ...); for n = 1, 2, ..., let m be the least integer > n such that L_n(n) divides L_n(m); L_{n+1}(k) = L_n(k) for any k <> m, L_{n+1}(m) = L_n(m)/L_n(n); a(n) = L_n(n).
%C A387025 Applying the same procedure to the powers of two yields A060546.
%C A387025 Applying the same procedure to the factorial numbers yields A006882.
%H A387025 Rémy Sigrist, <a href="/A387025/b387025.txt">Table of n, a(n) for n = 1..10000</a>
%F A387025 a(p) = p for any prime number p.
%F A387025 a(2*p) = 1 or 2 for any prime number p.
%e A387025 The first terms are:
%e A387025 n a(n) L_n
%e A387025 -- ---- ------------------------------------------------------
%e A387025 1 1 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, ...
%e A387025 2 2 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, ...
%e A387025 3 3 1, 2, 3, 2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, ...
%e A387025 4 2 1, 2, 3, 2, 5, 2, 7, 8, 9, 10, 11, 12, 13, 14, 15, ...
%e A387025 5 5 1, 2, 3, 2, 5, 1, 7, 8, 9, 10, 11, 12, 13, 14, 15, ...
%e A387025 6 1 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 12, 13, 14, 15, ...
%e A387025 7 7 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 12, 13, 14, 15, ...
%e A387025 8 8 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 12, 13, 2, 15, ...
%e A387025 9 9 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 12, 13, 2, 15, ...
%e A387025 10 2 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 12, 13, 2, 15, ...
%e A387025 11 11 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 6, 13, 2, 15, ...
%e A387025 12 6 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 6, 13, 2, 15, ...
%e A387025 13 13 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 6, 13, 2, 15, ...
%e A387025 14 2 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 6, 13, 2, 15, ...
%e A387025 15 15 1, 2, 3, 2, 5, 1, 7, 8, 9, 2, 11, 6, 13, 2, 15, ...
%o A387025 (PARI) { for (n = 1, #a = vector(74, n, n), print1 (a[n]", "); forstep (k = ceil((n+1)/a[n])*a[n], #a, a[n], if (a[k] % a[n]==0, a[k] /= a[n]; break;););); }
%Y A387025 Cf. A006882, A060546.
%K A387025 nonn,new
%O A387025 1,2
%A A387025 _Rémy Sigrist_, Aug 13 2025