%I
%S 1,5,15,42,101,231,490,1002,1958,3718,6842,12310,21637,37338,63261,
%T 105558,173525,281589,451276,715220,1121505,1741630,2679689,4087968,
%U 6185689,9289091,13848650,20506255,30167357,44108109,64112359,92669720,133230930,190569292
%N Number of partitions of 3n+1.
%C Old name was: P(3*n + 1) where P(m) is the unrestricted partition of m and n = 1,2,3,... .
%C a(n) is also the number of partitions of 4n2 that include n as a part; see Comment at A000041.  _Clark Kimberling_, Mar 03 2014
%e If n=25 then P(3*25 + 1) = 9289091.
%t Table[PartitionsP[3 n + 1], {n, 0, 10}]
%o (PARI) a(n) = numbpart(3*n+1); \\ _Michel Marcus_, Mar 04 2014
%Y Cf. A000041.
%K nonn
%O 0,2
%A _Parthasarathy Nambi_, Nov 01 2005
%E Better name from _Clark Kimberling_, Mar 02 2014
