A183949 Number of strings of numbers x(i=1..n) in 0..5 with sum i^2*x(i) equal to n^2*5

1, 2, 4, 14, 53, 180, 656, 2195, 7250, 23044, 71123, 213368, 624425, 1784399, 4986210, 13657266, 36691985, 96863639, 251472815, 642811767, 1619203005, 4022796235, 9864987052, 23894800443, 57205375668, 135438579331, 317296680619

Offset

1,2

Comments

Column 5 of A183953

Links

R. H. Hardin, Table of n, a(n) for n = 1..54

Example

All solutions for n=4
..0....1....0....3....3....3....4....2....4....1....5....0....3....5
..3....1....4....0....1....4....3....3....2....5....4....0....5....0
..4....3....0....5....1....5....0....2....4....3....3....0....1....3
..2....3....4....2....4....1....4....3....2....2....2....5....3....3

Mathematica

r[n_, k_, s_] := r[n, k, s] = Which[s < 0, 0, n == 0, If[s == 0, 1, 0], True, Sum[r[n - 1, k, s - c*n^2], {c, 0, k}]];
T[n_, k_] := r[n, k, k*n^2];
a[n_] := T[n, 5];
Table[a[n], {n, 1, 40}] (* Jean-François Alcover, Jul 22 2022, after R. J. Mathar in A183953 *)

Crossrefs

Sequence in context: A038055 A006385 A322859 * A131180 A047990 A000939

Adjacent sequences: A183946 A183947 A183948 * A183950 A183951 A183952

Keyword

nonn

Author

R. H. Hardin, Jan 08 2011

Status

approved