cp's OEIS Frontend

A335572 Irregular triangle whose row n is the set of numbers d+n/d where d is a divisor of n.

%I A335572 #19 Jan 28 2021 11:13:36
%S A335572 2,3,4,4,5,6,5,7,8,6,9,6,10,7,11,12,7,8,13,14,9,15,8,16,8,10,17,18,9,
%T A335572 11,19,20,9,12,21,10,22,13,23,24,10,11,14,25,10,26,15,27,12,28,11,16,
%U A335572 29,30,11,13,17,31,32,12,18,33,14,34,19,35,12,36,12,13,15,20,37
%N A335572 Irregular triangle whose row n is the set of numbers d+n/d where d is a divisor of n.
%C A335572 The last term of row n is n+1.
%H A335572 Michel Marcus, <a href="/A335572/b335572.txt">Rows n=1..4000 of triangle, flattened</a>
%e A335572 Triangle begins:
%e A335572   [2]
%e A335572   [3]
%e A335572   [4]
%e A335572   [4, 5]
%e A335572   [6]
%e A335572   [5, 7]
%e A335572   [8]
%e A335572   [6, 9]
%e A335572   [6, 10]
%e A335572   [7, 11]
%e A335572   ...
%t A335572 Table[Map[# + n/# &, #[[-Ceiling[Length[#]/2] ;; -1 ]] ] &@ Divisors[n], {n, 36}] // Flatten (* _Michael De Vlieger_, Jan 27 2021 *)
%o A335572 (PARI) row(n) = my(d=divisors(n)); Set(vector(#d,k,d[k]+n/d[k]));
%Y A335572 Cf. A027750 (divisors of n), A038548 (row lengths), A063655 (1st column).
%K A335572 nonn,tabf
%O A335572 1,1
%A A335572 _Michel Marcus_, Jan 26 2021