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 A309759 Numbers that are sums of consecutive powers of 4. 4
 1, 4, 5, 16, 20, 21, 64, 80, 84, 85, 256, 320, 336, 340, 341, 1024, 1280, 1344, 1360, 1364, 1365, 4096, 5120, 5376, 5440, 5456, 5460, 5461, 16384, 20480, 21504, 21760, 21824, 21840, 21844, 21845, 65536, 81920, 86016, 87040, 87296, 87360, 87376, 87380 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numbers of the form (4^i - 4^j)/3 with i > j. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE 336 = 4^2 + 4^3 + 4^4, so 336 is in the sequence. +------+--------+ | a(n) | base 4*| +------+--------+ | 1 | 1 | | 4 | 10 | | 5 | 11 | | 16 | 100 | | 20 | 110 | | 21 | 111 | | 64 | 1000 | | 80 | 1100 | | 84 | 1110 | | 85 | 1111 | +------+--------+ * - a(n) written in base 4. MATHEMATICA Module[{nn=10, k}, k=4^Range[0, nn]; Table[Accumulate[Reverse[Take[k, n]]], {n, nn}]]//Flatten (* Harvey P. Dale, May 29 2021 *) CROSSREFS Cf. A000302, A000695, A023758, A038470, A309758, A309761. Sequence in context: A081345 A137527 A024854 * A025617 A227855 A078581 Adjacent sequences: A309756 A309757 A309758 * A309760 A309761 A309762 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Aug 15 2019 STATUS approved

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Last modified July 18 00:08 EDT 2024. Contains 374377 sequences. (Running on oeis4.)