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 A168251 a(n) = n^2 if n is odd, n^2*2^(n-2) if n is even. 1
 0, 1, 4, 9, 64, 25, 576, 49, 4096, 81, 25600, 121, 147456, 169, 802816, 225, 4194304, 289, 21233664, 361, 104857600, 441, 507510784, 529, 2415919104, 625, 11341398016, 729, 52613349376, 841, 241591910400, 961, 1099511627776, 1089, 4964982194176, 1225 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS This is the main diagonal of the following array defined by T(n,2k+1) = A168077(k) for odd column indices and T(n,2k) = A168077(2k)*2^n for even column indices: 0, 1, 1, 9, 4, 25, ... A168077 0, 1, 2, 9, 8, 25, ... A129194 0, 1, 4, 9, 16,25, ... A000290 0, 1, 8, 9, 32,25, ... 0, 1, 16,9, 64,25, ... A154615 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 FORMULA a(2n) = A128782(n). a(2n+1) = A016754(n). a(n) = +15*a(n-2) -87*a(n-4) +245*a(n-6) -348*a(n-8) +240*a(n-10) - 64*a(n-12). G.f.: x*(1 + 4*x - 6*x^2 + 4*x^3 - 23*x^4 - 36*x^5 + 212*x^6 + 44*x^7 - 336*x^8 - 16*x^9 - 64*x^10) / ( (1-x)^3*(2*x+1)^3*(1-2*x)^3*(1+x)^3 ). - R. J. Mathar, Sep 20 2011 a(n) = (n^2)*2^((n-2)*(1+(-1)^n)/2). - Luce ETIENNE, Feb 03 2015 MAPLE A168251 := proc(n)         if type(n, 'even') then                 n^2*2^n/4 ;         else                 n^2 ;         end if; end proc: # R. J. Mathar, Sep 20 2011 MATHEMATICA Table[(n^2)*2^((n - 2)*(1 + (-1)^n)/2), {n, 0, 50}] (* G. C. Greubel, Jul 16 2016 *) PROG (MAGMA) [(n^2)*2^((n-2)*(1+(-1)^n) div 2): n in [0..40]]; // Vincenzo Librandi, Jul 17 2016 CROSSREFS Sequence in context: A073658 A059479 A094083 * A062758 A217854 A028822 Adjacent sequences:  A168248 A168249 A168250 * A168252 A168253 A168254 KEYWORD nonn,easy AUTHOR Paul Curtz, Nov 21 2009 STATUS approved

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Last modified February 29 05:25 EST 2020. Contains 332353 sequences. (Running on oeis4.)