

A192282


Numbers n such that n and n+1 have same sum of antidivisors.


3



1, 8, 17, 120, 717, 729, 957, 8097, 10785, 12057, 35817, 44817, 52863, 58677, 59757, 76759, 95397, 102957, 114117, 119337, 182157, 206097, 215997, 230037, 253977, 263877, 269277, 271797, 295377, 321417, 402657, 435477, 483117, 485637, 510837, 586797, 589317
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OFFSET

1,2


COMMENTS

Like A002961 but using antidivisors.
Curiously 957 and 958 have same sum of divisors and same sum of antidivisors.


LINKS

Donovan Johnson, Table of n, a(n) for n = 1..1000


EXAMPLE

Antidivisors of 717 are 2, 5, 6, 7, 35, 41, 205, 287, 478 and their sum is 1066.
Antidivisors of 718 are 3, 4, 5, 7, 35, 41, 205, 287, 479 and their sum is 1066.


MAPLE

with(numtheory);
P:=proc(n)
local a, b, i, k;
b:=2;
for i from 4 to n do
a:=0;
for k from 2 to i1 do
if abs((i mod k) k/2) < 1 then a:=a+k; fi;
od;
if a=b then print(i1); fi;
b:=a;
od;
end:
P(200000);


CROSSREFS

Cf. A002961, A066272, A192283.
Sequence in context: A177129 A177178 A097405 * A088588 A041537 A153315
Adjacent sequences: A192279 A192280 A192281 * A192283 A192284 A192285


KEYWORD

nonn


AUTHOR

Paolo P. Lava, Jul 27 2011


EXTENSIONS

Initial term a(1)=1 inserted, a(2)=9 through a(20)=119337 verified, and a(21)a(28) added by John W. Layman, Aug 04 2011


STATUS

approved



