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A048241 Number of colors that can mixed with n >= 0 units of yellow, blue, red. 5
1, 4, 7, 14, 23, 41, 56, 89, 119, 164, 206, 281, 335, 437, 518, 626, 734, 902, 1019, 1226, 1382, 1592, 1787, 2084, 2288, 2618, 2888, 3239, 3545, 4007, 4307, 4832, 5240, 5750, 6206, 6818, 7268, 8006, 8573, 9281, 9881, 10781, 11375, 12362 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

T. D. Noe, Table of n, a(n) for n = 0..1000

FORMULA

a(n) = number of triples (i, j, k) with 0 <= i+j+k <= n and gcd(i, j, k) = 1.

a(n)=A048134(n)+1. - T. D. Noe, Jan 16 2007

EXAMPLE

a(2)=7: white, primary and secondary colors (null, Y^1, B^1, R^1, Y^1*B^1, Y^1*R^1, B^1*R^1).

MATHEMATICA

Accumulate[ Table[ Sum[ MoebiusMu[n/d]*(d+1)*(d+2)/2, {d, Divisors[n]}], {n, 0, 43}]] + 1 (* Jean-François Alcover, Oct 16 2013, after T. D. Noe *)

CROSSREFS

Cf. A048134, A048240.

Sequence in context: A146678 A146417 A008370 * A003404 A139025 A221107

Adjacent sequences:  A048238 A048239 A048240 * A048242 A048243 A048244

KEYWORD

nonn,easy,nice

AUTHOR

Jurjen N.E. Bos, N. J. A. Sloane, Robin Trew (trew(AT)hcs.harvard.edu)

STATUS

approved

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Last modified July 22 05:05 EDT 2017. Contains 289648 sequences.