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A362948
Numbers whose sum of (distinct) prime divisors (A008472) equals 5.
2
5, 6, 12, 18, 24, 25, 36, 48, 54, 72, 96, 108, 125, 144, 162, 192, 216, 288, 324, 384, 432, 486, 576, 625, 648, 768, 864, 972, 1152, 1296, 1458, 1536, 1728, 1944, 2304, 2592, 2916, 3072, 3125, 3456, 3888, 4374, 4608, 5184, 5832, 6144, 6912, 7776, 8748, 9216, 10368, 11664, 12288
OFFSET
1,1
LINKS
FORMULA
Union of A000351 = {5^k ; k > 0} and A033845 = {2^j*3^k, j,k > 0}.
Sum_{n>=1} 1/a(n) = 3/4. - Amiram Eldar, Jul 27 2023
MATHEMATICA
seq[max_] := Union[Join[5^Range[Floor[Log[5, max]]], Flatten@ Table[2^i*3^j, {i, 1, Log2[max]}, {j, 1, Log[3, max/2^i]}]]]; seq[13000] (* Amiram Eldar, Jul 27 2023 *)
PROG
(PARI) select( {is_A362948(n)=vecsum(factor(n, 0)[, 1])==5}, [1..11^4]) \\ alternatively: [n | n<-[1..11^4], A008472(n)==5]
CROSSREFS
Cf. A008472 (sopf), A000351 (5^n), A033845 (2^m*3^n).
Sequence in context: A127306 A319184 A231959 * A168145 A276407 A022310
KEYWORD
nonn,easy
AUTHOR
M. F. Hasler, Jul 20 2023
STATUS
approved