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A350631
a(n) is the smallest multiple of n that has at least twice as many divisors as n.
1
2, 6, 6, 12, 10, 24, 14, 24, 18, 30, 22, 60, 26, 42, 30, 48, 34, 72, 38, 60, 42, 66, 46, 120, 50, 78, 54, 84, 58, 120, 62, 96, 66, 102, 70, 180, 74, 114, 78, 120, 82, 168, 86, 132, 90, 138, 94, 240, 98, 150, 102, 156, 106, 216, 110, 168, 114, 174, 118, 360, 122, 186, 126
OFFSET
1,1
COMMENTS
a(n) = min(A129902(n), A195199(n)).
Mostly agrees with A129902, but occasionally with A195199.
698377680 is a value of n where a(n) is equal to A195199(n).
a(n) <= A053669(n)*n. - David A. Corneth, Jan 08 2022
LINKS
MAPLE
f:= proc(n) local t, k;
t:= 2*numtheory:-tau(n);
for k from 2*n by n do
if numtheory:-tau(k) >= t then return k fi
od
end proc:
map(f, [$1..100]); # Robert Israel, Jan 20 2022
MATHEMATICA
a[n_] := Module[{d = 2 * DivisorSigma[0, n], k = 2*n}, While[DivisorSigma[0, k] < d, k += n]; k]; Array[a, 100] (* Amiram Eldar, Jan 08 2022 *)
PROG
(PARI) a(n) = my(m=n, d=numdiv(n)); while(numdiv(m)<2*d, m+=n); m; \\ Michel Marcus, Jan 08 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
J. Lowell, Jan 08 2022
STATUS
approved