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

7,2

Links

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

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);

Crossrefs

Column k=7 of A256193.

Sequence in context: A061620 A260513 A001781 * A320755 A053308 A201458

Adjacent sequences: A258474 A258475 A258476 * A258478 A258479 A258480

Keyword

nonn

Author

Alois P. Heinz, May 31 2015

Status

approved