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 A242669 a(n) = n*floor(n/3). 5
 0, 0, 0, 3, 4, 5, 12, 14, 16, 27, 30, 33, 48, 52, 56, 75, 80, 85, 108, 114, 120, 147, 154, 161, 192, 200, 208, 243, 252, 261, 300, 310, 320, 363, 374, 385, 432, 444, 456, 507, 520, 533, 588, 602, 616, 675, 690, 705, 768, 784, 800, 867, 884, 901, 972, 990 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS For n = 0, 1, 2, 4, 8, 49, 98, 676, 1352, 9409, 18818, 131044, 262088, 1825201, 3650402, ... a(n) is a square. LINKS Bruno Berselli, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (1,0,2,-2,0,-1,1). FORMULA G.f.: x^3*(3 + x + x^2 + x^3)/((1 - x)^3*(1 + x + x^2)^2). a(3m) = A033428(m), a(3m+1) = A049451(m), a(3m+2) = A045944(m). MATHEMATICA Table[n Floor[n/3], {n, 0, 60}] PROG (MAGMA) [n*Floor(n/3): n in [0..60]]; (Sage) [n*floor(n/3) for n in (0..60)]; (PARI) a(n)=n\3*n \\ Charles R Greathouse IV, Oct 07 2015 CROSSREFS Cf. A000290: n^2; A010762: floor(n/2)*floor(n/3); A093353: n*floor(n/2); A213033: n*floor(n/2)*floor(n/3); A233035: n*floor(n/4). Cf. A033428, A045944, A049451. Sequence in context: A239356 A077034 A076601 * A090829 A236244 A141290 Adjacent sequences:  A242666 A242667 A242668 * A242670 A242671 A242672 KEYWORD nonn,easy AUTHOR Bruno Berselli, Jul 01 2014 STATUS approved

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Last modified December 10 12:30 EST 2019. Contains 329895 sequences. (Running on oeis4.)