A180277 Sum of the two members of the n-th pair of unitary amicable numbers.

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

1,1

Comments

This is to A161005 (Sums of pairs of amicable numbers), as unitary amicable pairs are to pairs of amicable numbers.

Links

Table of n, a(n) for n=1..28.

Peter Hagis, Jr., Unitary amicable numbers, Math. Comp., 25 (1971), 915-918.

Eric W. Weisstein, Unitary Amicable Pair

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}.

Example

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

Crossrefs

Cf. A002952, A002953, A161005, A180163.

Sequence in context: A049335 A004009 A269033 * A357257 A005950 A279746

Adjacent sequences: A180274 A180275 A180276 * A180278 A180279 A180280

Keyword

nonn

Author

Jonathan Vos Post, Aug 23 2010

Extensions

Extended by R. J. Mathar, Aug 26 2010

Status

approved