A385609 Partial sums of A090740.

1, 4, 5, 9, 10, 13, 14, 19, 20, 23, 24, 28, 29, 32, 33, 39, 40, 43, 44, 48, 49, 52, 53, 58, 59, 62, 63, 67, 68, 71, 72, 79, 80, 83, 84, 88, 89, 92, 93, 98, 99, 102, 103, 107, 108, 111, 112, 118, 119, 122, 123, 127, 128, 131, 132, 137, 138, 141, 142, 146, 147, 150, 151

Offset: 1

Author

Paolo Xausa, Jul 04 2025

Keywords

• nonn
• easy

Comments

Prepended with 0, a trisection of A385608.

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000120, A090740, A385608.

Programs

Mathematica

A385609[n_] := 2*n + Quotient[n, 2] - DigitSum[n, 2];
Array[A385609, 100] (* or *)
Accumulate[IntegerExponent[3^Range[100] - 1, 2]]

Formula

a(n) = Sum_{k=1..n} A090740(k).

a(n) = 2*n + floor(n/2) - A000120(n).

a(n) = A385608(n*3).