A337921 - OEIS

A337921

a(n) is the sum of (3^n mod 2^k) for k such that 2^k < 3^n.

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

1,2

COMMENTS

a(n) == A056576(n) (mod 2).

LINKS

Robert P. P. McKone, Table of n, a(n) for n = 1..1000

EXAMPLE

a(3) = (3^3 mod 2^1) + (3^3 mod 2^2) + (3^3 mod 2^3) + (3^3 mod 2^4) = 18.

MAPLE

f:= proc(n) local k; add(3 &^ n mod 2^k, k = 1 .. ilog2(3^n)) end proc:

map(f, [$1..100]);