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A340285 Number of partitions of n into 3 parts such that the largest part is relatively prime to each of the other two parts. 2
0, 0, 1, 1, 1, 2, 2, 3, 3, 5, 5, 7, 6, 9, 8, 11, 10, 16, 12, 18, 15, 20, 19, 28, 21, 30, 25, 34, 27, 44, 30, 44, 36, 50, 39, 60, 43, 62, 51, 69, 52, 85, 56, 83, 68, 86, 68, 109, 71, 109, 84, 110, 84, 138, 91, 132, 105, 138, 104, 176, 111, 162, 131, 171, 127, 204, 129, 193 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..68.

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(n-i-k,k)) * floor(1/gcd(n-i-k,i)).

MATHEMATICA

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

CROSSREFS

Cf. A340283, A340284.

Sequence in context: A304430 A086609 A341140 * A341462 A035031 A035032

Adjacent sequences:  A340282 A340283 A340284 * A340286 A340287 A340288

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, Jan 02 2021

STATUS

approved

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Last modified November 29 13:17 EST 2021. Contains 349416 sequences. (Running on oeis4.)