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 A020537 a(n) = 4*8^n - 3*2^n. 1
 1, 26, 244, 2024, 16336, 130976, 1048384, 8388224, 67108096, 536869376, 4294964224, 34359732224, 274877894656, 2199023230976, 17592185995264, 140737488257024, 1125899906646016, 9007199254347776, 72057594037141504, 576460752301850624, 4611686018424242176 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS 3rd Chebyshev polynomial (first kind) evaluated at powers of 2. LINKS Colin Barker, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (10,-16). FORMULA a(n) = 10*a(n-1)-16*a(n-2). - Colin Barker, May 03 2015 G.f.: (16*x+1) / ((2*x-1)*(8*x-1)). - Colin Barker, May 03 2015 MAPLE with(orthopoly):seq(T(3, 2^i), i=0..24); MATHEMATICA Table[ChebyshevT[3, 2^n], {n, 1, 40}] (* Vladimir Joseph Stephan Orlovsky, Nov 03 2009 *) PROG (PARI) a(n) = polchebyshev(3, 1, 2^n); \\ Michel Marcus, Dec 28 2014 (PARI) Vec((16*x+1)/((2*x-1)*(8*x-1)) + O(x^100)) \\ Colin Barker, May 03 2015 CROSSREFS Sequence in context: A293614 A245873 A275880 * A184461 A088889 A060105 Adjacent sequences:  A020534 A020535 A020536 * A020538 A020539 A020540 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified August 1 07:45 EDT 2021. Contains 346384 sequences. (Running on oeis4.)