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A340279 Number of partitions of n into 3 parts such that the smallest part is relatively prime to at least one other part. 2
0, 0, 1, 1, 2, 2, 4, 4, 6, 6, 10, 8, 14, 12, 16, 16, 24, 18, 30, 24, 32, 30, 43, 32, 49, 42, 54, 48, 68, 48, 78, 64, 80, 72, 93, 72, 110, 90, 111, 96, 134, 96, 148, 120, 144, 132, 175, 128, 187, 150, 189, 168, 221, 162, 230, 191, 236, 209, 273, 192, 293, 239, 285, 255 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..64.

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

MATHEMATICA

Table[Sum[Sum[Sign[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. A340278, A340280.

Sequence in context: A328422 A029009 A340280 * A343100 A023023 A184157

Adjacent sequences:  A340276 A340277 A340278 * A340280 A340281 A340282

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, Jan 02 2021

STATUS

approved

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Last modified May 19 11:44 EDT 2022. Contains 353833 sequences. (Running on oeis4.)