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A074898
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Impossible values for sum of anti-divisors of n.
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2
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1, 6, 7, 9, 11, 15, 17, 20, 21, 25, 26, 27, 29, 31, 33, 35, 37, 38, 43, 44, 45, 47, 49, 51, 53, 59, 61, 62, 63, 65, 67, 68, 69, 71, 73, 75, 77, 79, 81, 82, 83, 85, 87, 89, 91, 93, 95, 97, 99, 100, 103, 105, 109, 111, 113, 115, 117, 119, 120, 121, 123, 125, 127, 128, 129, 131, 133, 134, 135, 137, 139, 141, 143, 145, 146, 149, 151, 153, 155, 157, 158, 159, 161, 163, 165, 167, 168, 169, 170, 171
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| See A066272 for definition of anti-divisor.
Like A005114 but using anti-divisors. [Paolo P. Lava, Jul 06 2011]
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LINKS
| Paolo P. Lava, Table of n, a(n) for n = 1..9999
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MAPLE
| with(numtheory);
P:=proc(i)
local a, b, c, d, k, n, s, v;
v:=array(3..i); d:={};
for n from 1 to 24772 do d:=d union {n}; od;
for n from 3 by 1 to i do
a:={};
for k from 2 to n-1 do
if abs((n mod k)- k/2) < 1 then a:=a union {k}; fi;
od;
b:=nops(a); c:=op(a); s:=0;
if b>1 then
for k from 1 to b do s:=s+c[k]; od;
else s:=c;
fi;
v[n]:=s;
od;
a:={};
for n from 3 to i do a:=a union {v[n]}; od;
b:=d minus a; b:=sort([op(b)]);
end:
P(10000);
# Paolo P. Lava, Jul 06 2011.
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CROSSREFS
| Cf. A005114, A066417.
Sequence in context: A081053 A022892 A120164 * A175221 A094010 A100348
Adjacent sequences: A074895 A074896 A074897 * A074899 A074900 A074901
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KEYWORD
| nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Sep 14 2002
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EXTENSIONS
| More terms from Paolo P. Lava (paoloplava(AT)gmail.com), Jul 06 2011
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