A091889 Number of partitions of n into sums of exactly two distinct powers of 2.

0, 0, 1, 0, 1, 2, 0, 1, 3, 2, 2, 5, 2, 3, 8, 4, 6, 12, 6, 11, 16, 11, 16, 24, 17, 23, 34, 26, 35, 50, 35, 50, 67, 55, 72, 93, 76, 99, 126, 112, 135, 171, 150, 186, 229, 210, 249, 304, 280, 336, 398, 380, 443, 526, 499, 584, 680, 665, 759, 886, 858, 985, 1136, 1123

Offset: 1

Author

Reinhard Zumkeller, Feb 10 2004

Keywords

• nonn

Examples

			a(9)=3: 9 = (2^3+2^0) = (2^2+2^1)+(2^1+2^0) = (2^1+2^0)+(2^1+2^0)+(2^1+2^0).
		

Links

• David A. Corneth, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A018819, A018900, A091890, A000120, A000041, A091893, A091891.

Programs

Mathematica

With[{max = 64}, m = Select[Range[max], DigitCount[#, 2, 1] == 2 &]; a[n_] := Length@ IntegerPartitions[n, n, m]; Array[a, max]] (* Amiram Eldar, Aug 01 2023 *)