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A340282 Number of partitions of n into 3 parts such that the largest part is relatively prime to at least one other part. 1
0, 0, 1, 1, 2, 2, 4, 4, 6, 6, 9, 8, 13, 12, 16, 16, 22, 18, 28, 24, 31, 30, 38, 32, 46, 41, 52, 47, 63, 48, 72, 63, 78, 70, 89, 72, 101, 88, 107, 95, 125, 96, 139, 118, 141, 131, 164, 128, 180, 148, 184, 166, 209, 161, 222, 189, 228, 205, 258, 192, 277, 236, 279, 250, 310 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..65.

Index entries for sequences related to partitions

FORMULA

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

MATHEMATICA

Table[Sum[Sum[Sign[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. A340279, A340280.

Sequence in context: A238132 A278296 A332305 * A008642 A001364 A029010

Adjacent sequences:  A340279 A340280 A340281 * A340283 A340284 A340285

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, Jan 02 2021

STATUS

approved

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Last modified January 23 14:34 EST 2022. Contains 350512 sequences. (Running on oeis4.)