A199123 - OEIS

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A199123

Number of partitions of n into distinct terms of (2,3)-Ulam sequence, cf. A001857.

1, 0, 1, 1, 0, 2, 0, 2, 2, 2, 3, 2, 3, 3, 4, 4, 5, 5, 6, 6, 6, 8, 8, 9, 11, 10, 12, 14, 12, 17, 16, 17, 22, 19, 24, 25, 25, 30, 30, 33, 37, 37, 42, 45, 46, 52, 54, 57, 64, 66, 69, 79, 76, 87, 93, 91, 109, 105, 115, 126, 123, 140, 144, 151, 166, 169, 180, 193

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,6

LINKS

Table of n, a(n) for n=0..67.

Eric Weisstein's World of Mathematics, Ulam Sequence

Wikipedia, Ulam number

Index entries for Ulam numbers

EXAMPLE

The first terms of A001857 are 2, 3, 5, 7, 8, 9, 13, 14, 18, 19, 24, ...

a(20) = #{18+2, 13+7, 13+5+2, 9+8+3, 8+7+5, 8+7+3+2} = 6;

a(21) = #{19+2, 18+3, 14+7, 14+5+2, 13+8, 13+5+3, 9+7+5, 9+7+3+2} = 8.