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 A339473 Numbers k such that floor(sqrt(k)) divides k^2, but does not divide k. 0
 18, 22, 68, 76, 84, 87, 93, 96, 150, 162, 260, 264, 268, 276, 280, 284, 330, 336, 348, 354, 410, 430, 588, 612, 630, 635, 640, 645, 655, 660, 665, 670, 738, 747, 765, 774, 798, 826, 1032, 1040, 1048, 1064, 1072, 1080, 1302, 1308, 1314, 1320, 1326, 1338, 1344, 1350 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 18 is in the sequence since floor(sqrt(18)) = 4, which does not divide 18, but it does divide 18^2 = 324. MATHEMATICA Flatten[Table[If[(1 - Ceiling[n^2/Floor[Sqrt[n]]] + Floor[n^2/Floor[Sqrt[n]]]) (Ceiling[n/Floor[Sqrt[n]]] - Floor[n/Floor[Sqrt[n]]]) == 1, n, {}], {n, 2000}]] PROG (PARI) isok(k) = (k % sqrtint(k)) && !(k^2 % sqrtint(k)); \\ Michel Marcus, Apr 24 2021 (Python) from math import isqrt def ok(k): r = isqrt(k); return k % r != 0 and k**2 % r == 0 print(list(filter(ok, range(1, 1351)))) # Michael S. Branicky, Apr 24 2021 CROSSREFS Cf. A006446. Sequence in context: A290172 A031407 A267826 * A002505 A182438 A050772 Adjacent sequences:  A339470 A339471 A339472 * A339474 A339475 A339476 KEYWORD nonn AUTHOR Wesley Ivan Hurt, Apr 24 2021 STATUS approved

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Last modified August 1 05:51 EDT 2021. Contains 346384 sequences. (Running on oeis4.)