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A082895 Closest number to sigma(n) = A000203(n) which is divisible by n. 3
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

LINKS

Table of n, a(n) for n=1..69.

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;

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

Cf. A082893-A082900, A000203.

Sequence in context: A280166 A257088 A022998 * A086938 A007015 A114562

Adjacent sequences:  A082892 A082893 A082894 * A082896 A082897 A082898

KEYWORD

nonn

AUTHOR

Labos Elemer, Apr 22 2003

STATUS

approved

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Last modified March 20 15:43 EDT 2019. Contains 321345 sequences. (Running on oeis4.)