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 A245062 #29 Feb 16 2025 08:33:23 %S A245062 1,2,10,3,20,100,4,12,110,1000,5,40,21,200,10000,6,50,112,30,1010, %T A245062 100000,7,24,140,220,102,1100,1000000,8,70,42,230,400,111,2000, %U A245062 10000000,9,80,133,60,320,1012,120,10010,100000000,190,18,152,322,114,410,1120,201,10100,1000000000 %N A245062 Array read by upward antidiagonals: Niven (or Harshad) numbers arranged in rows by their digit sums. %C A245062 The n-th row contains in increasing order all multiples of n with digit sum n. %C A245062 See A005349 for definitions and references. %H A245062 Alois P. Heinz, <a href="/A245062/b245062.txt">Antidiagonals n = 1..70, flattened</a> %H A245062 Eric W. Weisstein, <a href="https://mathworld.wolfram.com/HarshadNumber.html">Harshad Number</a>, from MathWorld. %e A245062 Array begins as: %e A245062 1 10 100 1000 10000 100000 1000000 10000000 100000000 1000000000 %e A245062 2 20 110 200 1010 1100 2000 10010 10100 11000 %e A245062 3 12 21 30 102 111 120 201 210 300 %e A245062 4 40 112 220 400 1012 1120 1300 2020 2200 %e A245062 5 50 140 230 320 410 500 1040 1130 1220 %e A245062 6 24 42 60 114 132 150 204 222 240 %e A245062 7 70 133 322 511 700 1015 1141 1204 1330 %e A245062 8 80 152 224 440 512 800 1016 1160 1232 %e A245062 9 18 27 36 45 54 63 72 81 90 %e A245062 190 280 370 460 550 640 730 820 910 1090 %Y A245062 Cf. A002998 (column 1), A245065 (column 2). %Y A245062 Cf. A011557 (row 1), A069537 (row 2), A052217 (row 3), A063997 (row 4), A069540 (row 5), A062768 (row 6), A063416 (row 7), A069543 (row 8), A052223 (row 9). %Y A245062 Cf. A082260 (main diagonal). %Y A245062 Cf. A007953, A005349 (Niven or Harshad numbers). %Y A245062 Cf. A082259. %K A245062 nonn,base,tabl %O A245062 1,2 %A A245062 _L. Edson Jeffery_, Jul 10 2014