A002221 - OEIS

A002221

a(n) is the number of partitions of 4n that can be obtained by adding together four (not necessarily distinct) partitions of n.
(Formerly M3861 N1583)

1, 5, 15, 55, 140, 448, 1022, 2710, 6048, 14114, 28831, 64091, 123649, 251295, 476835, 916972, 1654044, 3080159, 5377431, 9624588, 16490017, 28433473, 47423409, 80279375

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

REFERENCES

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..24.

N. Metropolis and P. R. Stein, An elementary solution to a problem in restricted partitions, J. Combin. Theory, 9 (1970), 365-376.

CROSSREFS

See A002219 for further details. Cf. A002220, A002222, A213074.

A column of A213086.