In mathematics, a natural number n is called k-almost prime iff Ω(n) = k, where Ω(n) is the sum of the exponents in the prime decomposition of n:
k k-almost prime numbers Sloane sequence 1 2, 3, 5, 7, 11, 13, 17, 19, ... A000040 2 4, 6, 9, 10, 14, 15, 21, 22, ... A001358 3 8, 12, 18, 20, 27, 28, 30, ... A014612 4 16, 24, 36, 40, 54, 56, 60, ... A014613 5 32, 48, 72, 80, 108, 112, ... A014614 6 64, 96, 144, 160, 216, 224, ... A046306 7 128, 192, 288, 320, 432, 448, ... A046308 8 256, 384, 576, 640, 864, 896, ... A046310 9 512, 768, 1152, 1280, 1728, ... A046312 10 1024, 1536, 2304, 2560, ... A046314 11 2048, 3072, 4608, 5120, ... A069272 12 4096, 6144, 9216, 10240, ... A069273 13 8192, 12288, 18432, 20480, ... A069274 14 16384, 24576, 36864, 40960, ... A069275 15 32768, 49152, 73728, 81920, ... A069276 16 65536, 98304, 147456, ... A069277 17 131072, 196608, 294912, ... A069278 18 262144, 393216, 589824, ... A069279 19 524288, 786432, 1179648, ... A069280 20 1048576, 1572864, 2359296, ... A069281
