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A337921
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a(n) is the sum of (3^n mod 2^k) for k such that 2^k < 3^n.
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1
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1, 3, 18, 38, 195, 585, 607, 3948, 11976, 42415, 127921, 56067, 666938, 2082798, 10769251, 22610393, 110616780, 315726436, 408228944, 2384863439, 7159829169, 23350950650, 74348867826, 49863537606, 401947783347, 1296027221145, 6159163094580, 13796041908620, 60717334308629, 181812784262527
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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a(3) = (3^3 mod 2^1) + (3^3 mod 2^2) + (3^3 mod 2^3) + (3^3 mod 2^4) = 18.
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MAPLE
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f:= proc(n) local k; add(3 &^ n mod 2^k, k = 1 .. ilog2(3^n)) end proc:
map(f, [$1..100]);
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MATHEMATICA
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PROG
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(PARI) a(n) = sum(k=1, logint(3^n, 2), lift(Mod(3, 2^k)^n)); \\ Michel Marcus, Jan 30 2021
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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