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A082895 Closest number to sigma(n) = A000203(n) which is divisible by n. 5
1, 4, 3, 8, 5, 12, 7, 16, 9, 20, 11, 24, 13, 28, 30, 32, 17, 36, 19, 40, 42, 44, 23, 72, 25, 52, 27, 56, 29, 60, 31, 64, 33, 68, 35, 108, 37, 76, 39, 80, 41, 84, 43, 88, 90, 92, 47, 144, 49, 100, 51, 104, 53, 108, 55, 112, 57, 116, 59, 180, 61, 124, 126, 128, 65, 132, 67, 136, 69 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
In the case of a tie, we round up. - Robert Israel, May 26 2019
LINKS
FORMULA
a(n) = n*floor((floor(n/2)+sigma(n))/n).
EXAMPLE
n=100: sigma[100]=217 is between 100=1.100 and 200=2.100
200 is closer to 217, so a[100]=200;
MAPLE
f:= proc(n) uses numtheory; n*floor((floor(n/2)+sigma(n))/n) end proc:
map(f, [$1..100]); # Robert Israel, May 26 2019
MATHEMATICA
Table[n*Floor[(Floor[n/2]+DivisorSigma[1, n])/n], {n, 1, 100}]
PROG
(PARI) a(n)=sigma(n)\/n*n \\ Charles R Greathouse IV, Feb 15 2013
CROSSREFS
Sequence in context: A280166 A257088 A022998 * A086938 A007015 A354139
KEYWORD
nonn,look
AUTHOR
Labos Elemer, Apr 22 2003
STATUS
approved

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Last modified April 15 05:10 EDT 2024. Contains 371667 sequences. (Running on oeis4.)