A080330 Index in A002858 of the smaller of the two Ulam numbers that sum to the n-th Ulam number.

0, 0, 1, 1, 2, 2, 3, 2, 3, 2, 6, 2, 6, 2, 7, 1, 5, 4, 11, 9, 3, 6, 8, 10, 12, 2, 3, 4, 6, 18, 19, 13, 16, 3, 17, 20, 2, 3, 2, 24, 6, 11, 3, 8, 2, 15, 2, 3, 2, 15, 20, 2, 8, 27, 13, 25, 3, 6, 18, 2, 15, 2, 15, 25, 11, 6, 10, 2, 17, 3, 2, 15, 2, 3, 27, 20, 15, 20, 2, 25, 27, 42, 2, 15

Offset

1,5

Comments

The first two are zero because the Ulam sequence (A002858) is initialized for those terms. The terms of the sum are in A080328 and A080329 and the indices are in A080330 and A080331.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, PARI program for A080330

Example

The 11th Ulam number (26) is the sum of the 6th Ulam number (8) and the 10th Ulam number (18), so a(11)=6.

Prog

(PARI) See Links section.

Crossrefs

Cf. A002858, A080328, A080329, A080331.

Sequence in context: A096013 A072380 A144910 * A342905 A356741 A152872

Adjacent sequences: A080327 A080328 A080329 * A080331 A080332 A080333

Keyword

nonn

Author

Jud McCranie, Feb 15 2003

Status

approved