A120611 Sum of previous term and preceding divisors.
1, 2, 3, 4, 7, 8, 15, 19, 20, 27, 31, 32, 47, 48, 66, 72, 90, 111, 115, 116, 123, 127, 128, 175, 183, 187, 188, 242, 245, 253, 254, 384, 610, 613, 614, 617, 618, 624, 690, 826, 836, 862, 865, 866, 869, 870, 891, 922, 925, 926, 929, 930, 982, 985, 986, 989, 990
Offset: 1
Keywords
Links
- Ivan Neretin, Table of n, a(n) for n = 1..10000
Programs
-
Mathematica
a = {1, 2}; Do[AppendTo[a, Plus @@ Intersection[a, Divisors[a[[-1]]]]], {n, 3, 57}]; a (* Ivan Neretin, May 13 2015 *)
Formula
a(1) = 1, a(2) = 2, for n>=2, a(n+1) = a(n) + sum_{1<=k