A080570 Number of 1's in partition of n-th Ulam number into sum of two distinct Ulam numbers.

1, 0, 1, 2, 2, 2, 3, 3, 4, 4, 6, 6, 8, 8, 11, 12, 13, 15, 14, 17, 18, 19, 20, 21, 23, 23, 24, 26, 28, 32, 31, 32, 35, 36, 37, 43, 43, 44, 44, 45, 47, 50, 51, 53, 53, 56, 56, 57, 57, 61, 62, 62, 65, 68, 73, 76, 77, 78, 83, 83, 84, 84, 87, 88, 90, 92, 94, 94, 97, 98, 98, 101, 101

Offset

1,4

Links

Table of n, a(n) for n=1..73.

Example

For n=7: A002858(7) = 11 = 3+8 = (1+2)+(2+6) = (1+2)+(2+(2+4)) = (1+2)+(2+(2+(1+3))) = (1+2)+(2+(2+(1+(1+2)))). Number of 1's in (1+2)+(2+(2+(1+(1+2)))) is 3, so a(7) = 3.

Crossrefs

Cf. A002858.

Sequence in context: A032739 A240868 A029149 * A163001 A239913 A323701

Adjacent sequences: A080567 A080568 A080569 * A080571 A080572 A080573

Keyword

easy,nonn

Author

Naohiro Nomoto, Feb 22 2003

Status

approved