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 A320699 Numbers whose product of prime indices is a nonprime prime power (A246547). 2
 7, 9, 14, 18, 19, 21, 23, 25, 27, 28, 36, 38, 42, 46, 49, 50, 53, 54, 56, 57, 63, 72, 76, 81, 84, 92, 97, 98, 100, 103, 106, 108, 112, 114, 115, 121, 125, 126, 131, 133, 144, 147, 152, 159, 162, 168, 171, 184, 189, 194, 196, 200, 206, 212, 216, 224, 227, 228 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS First differs from A320325 at a(43) = 152, A320325(43) = 151. 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..58. Index entries for sequences computed from indices in prime factorization EXAMPLE The sequence of all integer partitions whose Heinz numbers belong to the sequence begins: (4), (2,2), (4,1), (2,2,1), (8), (4,2), (9), (3,3), (2,2,2), (4,1,1), (2,2,1,1), (8,1), (4,2,1), (9,1), (4,4), (3,3,1), (16), (2,2,2,1), (4,1,1,1), (8,2), (4,2,2), (2,2,1,1,1), (8,1,1), (2,2,2,2), (4,2,1,1), (9,1,1), (25), (4,4,1), (3,3,1,1). MATHEMATICA Select[Range[100], With[{x=Times@@Cases[FactorInteger[#], {p_, k_}:>PrimePi[p]^k]}, !PrimeQ[x]&&PrimePowerQ[x]]&] CROSSREFS Cf. A000720, A000961, A001597, A003963, A056239, A064573, A112798, A246547, A246655, A279787, A320322, A320325, A320698, A320700. Sequence in context: A116025 A344011 A320325 * A332514 A353168 A305214 Adjacent sequences: A320696 A320697 A320698 * A320700 A320701 A320702 KEYWORD nonn AUTHOR Gus Wiseman, Oct 19 2018 STATUS approved

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Last modified August 5 04:43 EDT 2024. Contains 374935 sequences. (Running on oeis4.)