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 A069559 #9 Sep 19 2024 21:42:40 %S A069559 1,3,6,15,21,28,45,66,325,666,946,1128,1326,2145,2346,2628,2926,4186, %T A069559 8128,8385,8646,8911,11325,11628,14365,18145,18915,51681,52326,54615, %U A069559 54946,58311,111628,118341,152628,214185,258121,614386,1152921,1211346 %N A069559 Triangular numbers in which the k-th significant digit either divides k or is a multiple of k. %C A069559 If the smallest prime divisor of n is > 7 then the n-th digit is 1. %e A069559 8646 is a member in which the fourth digit is 8 a multiple of 4, the third one is 6 a multiple of 3, the second one is 4 a multiple of 2 and the least significant digit is 6. %Y A069559 Intersection of A000217 and A069570. %Y A069559 Cf. A069556, A069557, A069558. %K A069559 base,nonn %O A069559 1,2 %A A069559 _Amarnath Murthy_, Mar 22 2002 %E A069559 More terms from _Sascha Kurz_, Mar 23 2002 %E A069559 Offset changed by _Andrew Howroyd_, Sep 19 2024