A306720 Even numbers that are not the sum of two unitary abundant numbers (not necessarily distinct).

2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 62, 64, 66, 68, 70, 74, 76, 78, 80, 82, 86, 88, 90, 92, 94, 98, 102, 104, 106, 110, 114, 116, 118, 122, 124, 126, 128, 130, 134, 138, 142, 146, 150

Offset

1,1

Comments

The unitary version of A048242.

a(6066) = 530086 is the last term. te Riele proved that every even number larger than 530086 is the sum of two unitary abundant numbers (not necessarily distinct). The corresponding sequence of odd numbers is also finite, but he did not calculate the last term, and only showed that it is below 2004452254833.

Links

Amiram Eldar, Table of n, a(n) for n = 1..6066

Herman J. J. te Riele, On the representation of the positive integers as the sum of two unitary abundant numbers, Stichting Mathematisch Centrum, Numerieke Wiskunde NW 19/75 (1975).

Example

Since the unitary abundant numbers begin with 30, 42, 66, 70, ... the first integers which are missing from this sequence are 60 = 30 + 30, 72 = 30 +42, 84 = 42 + 42, 96 = 30 + 66, 100 = 30 + 70, ...

Crossrefs

Cf. A034683, A048242.

Sequence in context: A122080 A105360 A379511 * A084564 A053228 A368861

Adjacent sequences: A306717 A306718 A306719 * A306721 A306722 A306723

Keyword

nonn,fini,full

Author

Amiram Eldar, Mar 06 2019

Status

approved