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 A326158 Nonprime squarefree numbers whose product of prime indices is divisible by their sum of prime indices. 11
 30, 65, 154, 165, 190, 259, 273, 385, 390, 435, 442, 481, 506, 561, 595, 609, 658, 714, 741, 781, 874, 935, 1001, 1110, 1118, 1173, 1254, 1281, 1330, 1363, 1403, 1430, 1455, 1469, 1495, 1505, 1653, 1691, 1771, 1786, 1794, 1798, 1887, 1958, 2035, 2067, 2139 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE The sequence of terms together with their prime indices begins: 30: {1,2,3} 65: {3,6} 154: {1,4,5} 165: {2,3,5} 190: {1,3,8} 259: {4,12} 273: {2,4,6} 385: {3,4,5} 390: {1,2,3,6} 435: {2,3,10} 442: {1,6,7} 481: {6,12} 506: {1,5,9} 561: {2,5,7} 595: {3,4,7} 609: {2,4,10} 658: {1,4,15} 714: {1,2,4,7} 741: {2,6,8} 781: {5,20} MATHEMATICA primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]]; Select[Range[2, 1000], !PrimeQ[#]&&SquareFreeQ[#]&&Divisible[Times@@primeMS[#], Plus@@primeMS[#]]&] CROSSREFS Satisfies A056239(a(n))|A003963(a(n)). The case with squarefree numbers included is A326150. The case with primes and squarefree numbers included is A326149. Cf. A057567, A057568, A112798, A301987. Cf. A325037, A325042, A325044, A326151, A326153/A326154, A326155, A326156. Sequence in context: A042798 A320705 A132771 * A300790 A175259 A044132 Adjacent sequences: A326155 A326156 A326157 * A326159 A326160 A326161 KEYWORD nonn AUTHOR Gus Wiseman, Jun 10 2019 STATUS approved

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Last modified July 15 14:40 EDT 2024. Contains 374332 sequences. (Running on oeis4.)