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 A371970 Exponents k such that the binary expansion of 3^k has an even number of ones. 2
 1, 2, 3, 5, 6, 8, 9, 12, 14, 17, 18, 21, 23, 24, 25, 26, 27, 31, 32, 33, 35, 37, 38, 39, 40, 42, 44, 45, 47, 51, 52, 55, 57, 58, 59, 60, 61, 64, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 81, 96, 99, 102, 104, 105, 106, 109, 112, 116, 127, 131, 132, 133, 134, 135, 136 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Hugo Pfoertner, Table of n, a(n) for n = 1..10000 MAPLE q:= n-> is(add(i, i=Bits[Split](3^n))::even): select(q, [\$0..150])[]; # Alois P. Heinz, Apr 24 2024 MATHEMATICA Select[Range[136], EvenQ@ DigitCount[3^#, 2, 1] &] (* Michael De Vlieger, Apr 24 2024 *) PROG (PARI) is_a371970(k) = hammingweight(3^k)%2 == 0 CROSSREFS Complement of A223024. Cf. A000120, A000244, A001969, A011754, A078839. Sequence in context: A280744 A331072 A096276 * A239091 A272341 A075725 Adjacent sequences: A371967 A371968 A371969 * A371971 A371972 A371973 KEYWORD nonn,base,easy AUTHOR Hugo Pfoertner, Apr 24 2024 STATUS approved

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Last modified August 11 15:31 EDT 2024. Contains 375073 sequences. (Running on oeis4.)