Number of ways to put n copies of 1,2,3,4 into sets.

Terms

a(0) =1a(1) =15a(2) =139a(3) =862a(4) =4079a(5) =15791a(6) =52450a(7) =154279a(8) =411180a(9) =1009741a(10) =2314278a(11) =5000125a(12) =10264997a(13) =20152950a(14) =38037517a(15) =69323949a(16) =122448455a(17) =210271756a(18) =351989816a(19) =575711716a(20) =921889652a(21) =1447822620a(22) =2233501928a(23) =3389114724a(24) =5064582169a(25) =7461570579a(26) =10848490675a(27) =15579077786a(28) =22115241763a(29) =31054971635