A180277 a(n) = A002952(n) + A002953(n).

240, 2400, 40320, 72576, 94080, 120960, 141120, 311040, 403200, 483840, 483840, 725760, 673920, 1010880, 1209600, 1497600, 1411200, 1612800, 1747200, 2246400, 2177280, 2371200, 2449440, 2419200, 2620800, 2903040, 3144960, 3110400

Offset: 1

Author

Jonathan Vos Post, Aug 23 2010

Keywords

• nonn
• less

Examples

			a(1) = 114 + 126 = 240 = 2^4 * 3 * 5.
a(2) = 1140 + 1260 = 2400 = 2^5 * 3 * 5^2.
a(10) = a(11) - why?
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..7896

Crossrefs

Cf. A002952, A002953, A161005, A180163.

Formula

a(n) = A002952(n) + A002953(n).

{(j+k) such that sigma*(j) = sigma*(k) = j+k, where sigma*(n) is the unitary divisor function A034448}.

Extensions

Extended by R. J. Mathar, Aug 26 2010

Shorter name using given formula from Joerg Arndt, Jul 29 2024