A244242 Number of partitions of n into 6 parts such that every i-th smallest part (counted with multiplicity) is different from i.
1, 6, 16, 31, 52, 76, 107, 143, 184, 233, 289, 354, 427, 512, 606, 716, 835, 972, 1122, 1292, 1476, 1685, 1909, 2161, 2432, 2734, 3057, 3417, 3799, 4222, 4673, 5168, 5693, 6270, 6879, 7545, 8249, 9014, 9821, 10698, 11619, 12616, 13665, 14795, 15981, 17259
Offset: 27
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 27..1000
- N. Guru Sharan and Armin Straub, Partitions with Durfee triangles of fixed size, arXiv:2507.19047 [math.CO], 2025. See p. 5.
Crossrefs
Column k=6 of A238406.
Formula
Conjectures from Chai Wah Wu, Apr 18 2024: (Start)
a(n) = a(n-1) + a(n-2) - a(n-5) - 2*a(n-7) + a(n-9) + a(n-10) + a(n-11) + a(n-12) - 2*a(n-14) - a(n-16) + a(n-19) + a(n-20) - a(n-21) for n > 57.
G.f.: x^27*(-x^30 + 2*x^25 + 2*x^24 + 2*x^23 + 4*x^22 + 2*x^21 + x^20 - 9*x^19 - 12*x^18 - 16*x^17 - 12*x^16 + x^15 + 13*x^14 + 24*x^13 + 25*x^12 + 20*x^11 + 3*x^10 - 11*x^9 - 23*x^8 - 22*x^7 - 15*x^6 - 6*x^5 + 5*x^4 + 9*x^3 + 9*x^2 + 5*x + 1)/((x - 1)^6*(x + 1)^3*(x^2 + 1)*(x^2 - x + 1)*(x^2 + x + 1)^2*(x^4 + x^3 + x^2 + x + 1)). (End)