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 A017967 Powers of sqrt(21) rounded down. 2
 1, 4, 21, 96, 441, 2020, 9261, 42439, 194481, 891223, 4084101, 18715701, 85766121, 393029741, 1801088541, 8253624572, 37822859361, 173326116021, 794280046581, 3639848436450, 16679880978201, 76436817165460 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..700 FORMULA a(n) = floor(sqrt(21^n)). - Vincenzo Librandi, Jun 24 2011 MATHEMATICA Floor[(Sqrt[21])^Range[0, 30]] (* Harvey P. Dale, May 08 2018 *) PROG (Magma) [Floor(Sqrt(21^n)): n in [0..30]]; // Vincenzo Librandi, Jun 24 2011 (PARI) a(n)=sqrtint(21^n) \\ Charles R Greathouse IV, Nov 18 2011 CROSSREFS Cf. A010477 (sqrt(21)). Sequence in context: A371309 A220574 A231377 * A292308 A076901 A080043 Adjacent sequences: A017964 A017965 A017966 * A017968 A017969 A017970 KEYWORD nonn AUTHOR N. J. A. Sloane STATUS approved

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Last modified August 8 08:46 EDT 2024. Contains 375018 sequences. (Running on oeis4.)