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 A341674 #10 Mar 07 2021 21:02:43 %S A341674 1,1,1,1,1,2,1,1,2,1,1,2,1,1,2,3,1,1,2,1,3,1,2,1,1,2,3,1,1,2,4,1,3,1, %T A341674 2,1,1,2,3,4,1,1,2,1,3,1,2,4,1,1,2,3,5,1,1,2,4,1,3,1,2,1,5,1,2,3,4,1, %U A341674 1,2,1,3,1,2,4,5,1,1,2,3,6,1,1,2,4,1,3 %N A341674 Irregular triangle read by rows giving the strictly inferior divisors of n. %C A341674 We define a divisor d|n to be strictly inferior if d < n/d. The number of strictly inferior divisors of n is A056924(n). %e A341674 Triangle begins: %e A341674 1: {} 16: 1,2 31: 1 %e A341674 2: 1 17: 1 32: 1,2,4 %e A341674 3: 1 18: 1,2,3 33: 1,3 %e A341674 4: 1 19: 1 34: 1,2 %e A341674 5: 1 20: 1,2,4 35: 1,5 %e A341674 6: 1,2 21: 1,3 36: 1,2,3,4 %e A341674 7: 1 22: 1,2 37: 1 %e A341674 8: 1,2 23: 1 38: 1,2 %e A341674 9: 1 24: 1,2,3,4 39: 1,3 %e A341674 10: 1,2 25: 1 40: 1,2,4,5 %e A341674 11: 1 26: 1,2 41: 1 %e A341674 12: 1,2,3 27: 1,3 42: 1,2,3,6 %e A341674 13: 1 28: 1,2,4 43: 1 %e A341674 14: 1,2 29: 1 44: 1,2,4 %e A341674 15: 1,3 30: 1,2,3,5 45: 1,3,5 %t A341674 Table[Select[Divisors[n],#<n/#&],{n,100}] %Y A341674 Initial terms are A000012. %Y A341674 Row lengths are A056924 (number of strictly inferior divisors). %Y A341674 Final terms are A060775. %Y A341674 Row sums are A070039 (sum of strictly inferior divisors). %Y A341674 The weakly inferior version is A161906. %Y A341674 The weakly superior version is A161908. %Y A341674 The odd terms are counted by A333805. %Y A341674 The prime terms are counted by A333806. %Y A341674 The squarefree terms are counted by A341596. %Y A341674 The strictly superior version is A341673. %Y A341674 The prime-power terms are counted by A341677. %Y A341674 A001221 counts prime divisors, with sum A001414. %Y A341674 A001222 counts prime-power divisors. %Y A341674 A005117 lists squarefree numbers. %Y A341674 A038548 counts superior (or inferior) divisors. %Y A341674 A207375 lists central divisors. %Y A341674 - Inferior: A033676, A063962, A066839, A069288, A217581, A333749, A333750. %Y A341674 - Superior: A033677, A051283, A059172, A063538, A063539, A070038, A116882, A116883, A341591, A341592, A341593, A341675, A341676. %Y A341674 - Strictly Superior: A048098, A064052, A140271, A238535, A341594, A341595, A341642, A341643, A341644, A341645, A341646. %Y A341674 Cf. A000005, A000203, A001055, A001248, A006530, A020639, A050320. %K A341674 nonn,tabf %O A341674 1,6 %A A341674 _Gus Wiseman_, Feb 23 2021