

A240968


Unitary antiperfect numbers.


0



5, 8, 10, 41, 206, 1066, 2412, 3281, 8086, 11570, 29525, 57012, 73728, 410390, 413486, 775130, 2391485, 2454146, 2937446, 64563520, 100531166, 152032126, 988747406
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OFFSET

1,1


COMMENTS

For any number x we consider the sum of its antidivisors which are coprime to x (unitary antidivisors). The sequence list the numbers for which this sum is equal to x.
Subset of A192270.
I found only 2 unitary antiamicable numbers: 18208, 20470.
No other terms < 2147000000. Jud McCranie, Sep 21 2019.


LINKS

Table of n, a(n) for n=1..23.


EXAMPLE

Antidivisors of 1066 are 3, 4, 9, 27, 52, 79, 164, 237, 711. The antidivisors which are coprime to 1066 are 3, 9, 27, 79, 237, 711 and their sum is 3 + 9 + 27 + 79 + 237 + 711 = 1066.


MAPLE

P:=proc(q) local a, k, n;
for n from 3 to q do a:=0; b:=0;
for k from 2 to n1 do if abs((n mod k)k/2)<1 then
if gcd(n, k)=1 then a:=a+k; fi; fi; od;
if n=a then print(n); fi; od; end: P(10^6);


CROSSREFS

Cf. A066272, A066417, A073930, A192270, A240979.
Sequence in context: A185001 A057154 A072524 * A187878 A191233 A314386
Adjacent sequences: A240965 A240966 A240967 * A240969 A240970 A240971


KEYWORD

nonn,more


AUTHOR

Paolo P. Lava, Aug 05 2014


EXTENSIONS

a(14)a(23) by Jud McCranie, Sep 21 2019.


STATUS

approved



