A394575 Anti-admirable numbers. A number k is anti-admirable if there exists an anti-divisor d of k such that A066417(k) - 2d = 2k.

143, 175, 247, 270, 280, 347, 368, 462, 522, 563, 697, 725, 833, 850, 963, 1073, 1102, 1372, 1755, 1852, 1943, 1995, 2632, 2712, 3097, 3140, 3608, 3630, 3713, 3780, 4208, 4284, 4312, 4343, 4703, 4862, 5460, 5652, 6097, 6435, 7227, 7277, 8415, 8508, 10062, 10327

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Example

Anti-divisors of 143 are 2, 3, 5, 7, 15, 19, 22, 26, 41, 57, 95 and their sum is 292. Then, 292 - 2*3 = 2*143 = 286.
Anti-divisors of 175 are 2, 3, 9, 10, 13, 14, 27, 39, 50, 70, 117 and their sum is 354. Then, 354 - 2*2 = 2*175 = 350.

Maple

P:=proc(q) local a, b, k, n, v; v:=[]; for n from 1 to q do a:=[]; b:=0;
for k from 2 to n-1 do if abs((n mod k)-k/2)<1 then a:=[op(a), k]; b:=b+k; fi; od;
for k from 1 to nops(a) do if 2*n=b-2*a[k] then v:=[op(v), n]; fi; od; od; op(v); end: P(10327);

Crossrefs

Cf. A066417, A111592.

Sequence in context: A097435 A350735 A073954 * A227868 A353059 A176876

Adjacent sequences: A394572 A394573 A394574 * A394576 A394577 A394578

Keyword

nonn,easy

Author

Paolo P. Lava, Mar 25 2026

Status

approved