A340276 -id:A340276 - cp's OEIS frontend

A340278 Number of partitions of n into 3 parts whose smallest and largest parts are relatively prime.

0, 0, 1, 1, 2, 2, 4, 4, 5, 6, 9, 8, 11, 11, 13, 15, 19, 18, 23, 22, 24, 26, 32, 31, 37, 38, 42, 43, 50, 47, 55, 55, 59, 62, 68, 68, 78, 78, 83, 85, 96, 93, 105, 104, 108, 112, 124, 121, 132, 131, 138, 141, 154, 151, 162, 164, 172, 176, 191, 187, 205, 205, 212, 217, 228, 226

Offset: 1

Wesley Ivan Hurt, Jan 02 2021

nonn

Index entries for sequences related to partitions

Cf. A023023, A340275, A340276.

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

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

A340275 Number of partitions of n into 3 parts whose smallest two parts are relatively prime.

Original entry on oeis.org

0, 0, 1, 1, 2, 2, 3, 4, 5, 5, 7, 8, 10, 11, 12, 13, 16, 17, 20, 22, 24, 25, 29, 30, 33, 35, 38, 40, 45, 47, 52, 55, 58, 60, 64, 66, 72, 75, 79, 81, 88, 90, 97, 101, 105, 108, 116, 119, 126, 130, 135, 139, 148, 151, 157, 161, 167, 171, 181, 183, 193, 198, 204, 209, 217, 221

Offset: 1

Wesley Ivan Hurt, Jan 02 2021

nonn

Index entries for sequences related to partitions

Cf. A023023, A340276, A340278.

Table[Sum[Sum[Floor[1/GCD[i, k]], {i, k, Floor[(n - k)/2]}], {k, Floor[n/3]}], {n, 100}]

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

cp's OEIS Frontend

A340278 Number of partitions of n into 3 parts whose smallest and largest parts are relatively prime.

Views

Author

Keywords

Links

Crossrefs

Programs

Mathematica

Formula