A258477 Number of partitions of n into two sorts of parts having exactly 7 parts of the second sort.

1, 9, 46, 175, 551, 1517, 3775, 8677, 18702, 38221, 74670, 140380, 255200, 450587, 775050, 1302820, 2144491, 3464614, 5501502, 8601609, 13254960, 20160072, 30285308, 44987881, 66117110, 96226698, 138744972, 198343467, 281212898, 395689440, 552693604, 766773242

Offset: 7

Author

Alois P. Heinz, May 31 2015

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 7..1000

Crossrefs

Column k=7 of A256193.

Programs

Maple

b:= proc(n, i) option remember; series(`if`(n=0, 1,
      `if`(i<1, 0, add(b(n-i*j, i-1)*add(x^t*
       binomial(j, t), t=0..min(7, j)), j=0..n/i))), x, 8)
    end:
a:= n-> coeff(b(n$2), x, 7):
seq(a(n), n=7..40);