A271113 Numbers not in the range of the sum of abundant divisors function.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 33, 34, 35, 37, 39, 41, 43, 45, 46, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139

Offset

1,2

Comments

Numbers which do not appear in A187795 or in A270660; that is, there is no integer N whose sum of abundant divisors is equal to a(n) for any n.

This is a finite sequence that contains every odd positive integer less than 945, twelve even integers with 46 being the largest, and has the prime number 20161 as its last term.

A048242 contains the first three primitive abundant numbers: 12, 18, 20.

Links

Table of n, a(n) for n=1..82.

Sin Hitotumatu, On the Limit for the Representation by the Sum of Two Abundant Numbers, Publications of the Research Institute for Mathematical Sciences of Kyoto University, 8 (1972/1973), 111-116.

Crossrefs

Cf. A005101, subsequence of A048242 and A263837, A048260, A187795, A270660 (complement).

Sequence in context: A067340 A263837 A283550 * A325369 A317101 A304449

Adjacent sequences: A271110 A271111 A271112 * A271114 A271115 A271116

Keyword

nonn,fini

Author

Timothy L. Tiffin, Jul 13 2016

Status

approved