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 A284018 The smallest square referenced in A038109 (Divisible exactly by the square of a prime). 3
 4, 9, 4, 9, 4, 25, 4, 4, 4, 9, 49, 25, 4, 4, 9, 4, 9, 25, 4, 4, 9, 4, 49, 9, 4, 4, 4, 9, 121, 4, 9, 4, 4, 9, 49, 4, 25, 9, 4, 4, 169, 9, 4, 25, 4, 4, 4, 9, 25, 4, 9, 4, 4, 9, 4, 9, 4, 121, 4, 49, 4, 4, 9, 4, 25, 4, 9, 4, 9, 289, 4, 49, 4, 9, 4, 9, 4, 4, 25, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = p^2 where p is the least prime whose exponent in the prime factorization of A038109(n) is exactly 2. - Robert Israel, Mar 28 2017 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE A038109(3)=12, 12 = 2*2*3, so 12 is divisible by the square of 2 which is 4. MAPLE N:= 1000: # to use the members of A038109 <= N P:= select(isprime, [\$1..floor(sqrt(N))]): S:= {}: for p in P do   Ks:= select(t -> t mod p <> 0, {\$1..floor(N/p^2)});   R:= map(`*`, Ks, p^2) minus S;   for r in R do B[r]:= p^2 od:   S:= S union R; od: A038109:= sort(convert(S, list)): seq(B[A038109[i]], i=1..nops(A038109)); # Robert Israel, Mar 28 2017 CROSSREFS Cf. A038109, A284017, A013929, A283919. Sequence in context: A141653 A071793 A010714 * A089090 A204919 A113484 Adjacent sequences:  A284015 A284016 A284017 * A284019 A284020 A284021 KEYWORD nonn AUTHOR Robert Price, Mar 18 2017 EXTENSIONS Corrected by Robert Israel, Mar 28 2017 STATUS approved

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Last modified May 31 22:45 EDT 2020. Contains 334756 sequences. (Running on oeis4.)