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 A069558 #18 May 04 2024 18:21:16 %S A069558 1,3,6,21,28,45,66,325,666,946,2346,2628,2926,8385,8646,52326,54946 %N A069558 Triangular numbers in which the k-th digit, numbering them from right to left, either divides k or is a nonzero multiple of k. Is 1 only when k has no other single-digit divisor (less than 10). %C A069558 The n-th digit is 1 only when the smallest prime divisor of n is > 7. %C A069558 Next term > 10^18. - _Sascha Kurz_, Mar 23 2002 %e A069558 8646 is a term in which, numbering the digits from right to left, %e A069558 the 1st digit is 6; %e A069558 the 2nd digit is 4, a multiple of 2; %e A069558 the 3rd digit is 6, a multiple of 3; %e A069558 the 4th digit is 8, a multiple of 4. %Y A069558 Cf. A000217, A069556, A069557, A069559. %K A069558 base,hard,more,nonn %O A069558 1,2 %A A069558 _Amarnath Murthy_, Mar 22 2002 %E A069558 Offset corrected by _Sean A. Irvine_, May 04 2024