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 A145849 a(n) = A145812(2n-1). 3
 1, 9, 33, 41, 129, 137, 161, 169, 513, 521, 545, 553, 641, 649, 673, 681, 2049, 2057, 2081, 2089, 2177, 2185, 2209, 2217, 2561, 2569, 2593, 2601, 2689, 2697, 2721, 2729, 8193, 8201, 8225, 8233, 8321, 8329, 8353, 8361, 8705, 8713, 8737, 8745, 8833, 8841, 8865, 8873, 10241 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Every positive odd integer m==3 (mod 8) is a unique sum of the form a(s)+2a(t), while other odd integers are not expressible in this form. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..5000 FORMULA If f(x) = Sum_{n>=1}x^a(n), abs(x) < 1, then f(x)*f(x^2) = x^3/(1 - x^8). MATHEMATICA a[n_] := 2 * FromDigits[IntegerDigits[2*n-2, 2], 4] + 1; Array[a, 50] (* Amiram Eldar, Dec 16 2018 *) PROG (PARI) a145812(n) = 2*fromdigits(binary(n-1), 4) + 1; a(n) = a145812(2*n-1); \\ Michel Marcus, Dec 13 2018 CROSSREFS Bisection of A145812. Sequence in context: A130444 A177697 A287534 * A111045 A020226 A175440 Adjacent sequences:  A145846 A145847 A145848 * A145850 A145851 A145852 KEYWORD nonn AUTHOR Vladimir Shevelev, Oct 21 2008 EXTENSIONS More terms from Michel Marcus, Dec 13 2018 STATUS approved

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Last modified June 13 16:17 EDT 2021. Contains 345008 sequences. (Running on oeis4.)