A292704 Unitary abundant numbers k such that k+2 is also unitary abundant.

1428, 20020, 49740, 63490, 107338, 137170, 142140, 195130, 218218, 315588, 340338, 380380, 382380, 497418, 514668, 555828, 578578, 580578, 602140, 626890, 672978, 711618, 740740, 786828, 795340, 811578, 860860, 862860, 885610, 897258, 904330, 907060, 940938

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

1428 is in the sequence since both 1428 and 1430 are unitary abundant: usigma(1428) = 2880 > 2*1428 and usigma(1430) = 3024 > 2*1430.

Mathematica

usigma[n_]:=If[n==1, 1, Times @@ (1+Power @@@ FactorInteger[n])];
uaQ[n_] := usigma[n] > 2 n; Select[Range@100000, uaQ[#] && uaQ[# + 2] &]

Crossrefs

Cf. A034683, A096399.

Sequence in context: A250582 A260283 A156853 * A321036 A094230 A353080

Adjacent sequences: A292701 A292702 A292703 * A292705 A292706 A292707

Keyword

nonn

Author

Amiram Eldar, Sep 21 2017

Status

approved