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A340283 Number of partitions of n into 3 parts such that the smallest part is relatively prime to each of the other two parts. 2
0, 0, 1, 1, 2, 2, 3, 4, 4, 5, 6, 8, 7, 10, 9, 12, 11, 17, 13, 20, 16, 21, 18, 29, 21, 31, 26, 35, 27, 46, 29, 46, 37, 50, 39, 62, 40, 63, 51, 70, 50, 87, 54, 85, 69, 88, 65, 112, 71, 111, 84, 112, 81, 140, 89, 134, 103, 138, 99, 178, 105, 164, 131, 171, 126, 207, 125, 195, 152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

Index entries for sequences related to partitions

FORMULA

a(n) = Sum_{k=1..floor(n/3)} Sum_{i=k..floor((n-k)/2)} floor(1/gcd(k,i)) * floor(1/gcd(k,n-i-k)).

MATHEMATICA

Table[Sum[Sum[Floor[1/GCD[k, i]]*Floor[1/GCD[k, n - i - k]], {i, k, Floor[(n - k)/2]}], {k, Floor[n/3]}], {n, 80}]

CROSSREFS

Cf. A340284, A340285.

Sequence in context: A029043 A296371 A337601 * A324744 A097920 A029042

Adjacent sequences:  A340280 A340281 A340282 * A340284 A340285 A340286

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, Jan 02 2021

STATUS

approved

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Last modified July 30 00:57 EDT 2021. Contains 346346 sequences. (Running on oeis4.)