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 A339496 #9 Dec 31 2020 13:13:19 %S A339496 1,3,3,6,3,4,10,7,4,7,15,7,4,7,6,21,13,10,7,6,12,28,13,10,7,6,12,8,36, %T A339496 21,10,15,6,12,8,15,45,21,19,15,6,12,8,15,13,55,31,19,15,16,12,8,15, %U A339496 13,18,66,31,19,15,16,12,8,15,13,18,12,78,43,31,27,16,24,8,15,13,18,12,28 %N A339496 T(n, k) = Sum(divisors(k) union {k*j : j = 2..floor(n/k)}). Triangle read by rows. %C A339496 For the connection with paths in the divisor graph of {1,...,n} see the comment in A339492. %e A339496 The triangle starts: %e A339496 [1] 1; %e A339496 [2] 3, 3; %e A339496 [3] 6, 3, 4; %e A339496 [4] 10, 7, 4, 7; %e A339496 [5] 15, 7, 4, 7, 6; %e A339496 [6] 21, 13, 10, 7, 6, 12; %e A339496 [7] 28, 13, 10, 7, 6, 12, 8; %e A339496 [8] 36, 21, 10, 15, 6, 12, 8, 15; %e A339496 [9] 45, 21, 19, 15, 6, 12, 8, 15, 13; %e A339496 [10] 55, 31, 19, 15, 16, 12, 8, 15, 13, 18. %p A339496 t := (n, k) -> NumberTheory:-Divisors(k) union {seq(k*j,j=2..n/k)}: %p A339496 T := (n, k) -> add(j, j = t(n, k)): %p A339496 for n from 1 to 10 do seq(T(n, k), k=1..n) od; %Y A339496 T(n, 1) = A000217(n), T(n, n) = A000203(n), T(2n, n) = A224880(n). %Y A339496 Cf. A339491, A339492, A339489. %K A339496 nonn,tabl %O A339496 1,2 %A A339496 _Peter Luschny_, Dec 31 2020