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 A326150 Nonprime numbers whose product of prime indices is divisible by their sum of prime indices. 7
 9, 30, 49, 63, 65, 81, 84, 108, 125, 150, 154, 165, 169, 190, 198, 200, 259, 264, 273, 333, 351, 361, 364, 385, 390, 435, 442, 468, 481, 490, 495, 506, 525, 561, 580, 595, 609, 624, 630, 658, 675, 700, 714, 741, 765, 781, 783, 810, 840, 841, 846, 874, 900, 918 (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 Table of n, a(n) for n=1..54. EXAMPLE The sequence of terms together with their prime indices begins: 9: {2,2} 30: {1,2,3} 49: {4,4} 63: {2,2,4} 65: {3,6} 81: {2,2,2,2} 84: {1,1,2,4} 108: {1,1,2,2,2} 125: {3,3,3} 150: {1,2,3,3} 154: {1,4,5} 165: {2,3,5} 169: {6,6} 190: {1,3,8} 198: {1,2,2,5} 200: {1,1,1,3,3} 259: {4,12} 264: {1,1,1,2,5} 273: {2,4,6} 333: {2,2,12} MATHEMATICA primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]]; Select[Range[2, 1000], !PrimeQ[#]&&Divisible[Times@@primeMS[#], Plus@@primeMS[#]]&] CROSSREFS Satisfies A056239(a(n))|A003963(a(n)). The case with primes included is A326149. The squarefree case A326158. Cf. A057567, A057568, A112798, A301987. Cf. A325037, A325042, A325044, A326151, A326153/A326154, A326155, A326156. Sequence in context: A158503 A179506 A185653 * A167154 A063150 A063161 Adjacent sequences: A326147 A326148 A326149 * A326151 A326152 A326153 KEYWORD nonn AUTHOR Gus Wiseman, Jun 09 2019 STATUS approved

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Last modified May 25 04:52 EDT 2024. Contains 372782 sequences. (Running on oeis4.)