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A199120

Number of partitions of n into terms of (1,4)-Ulam sequence, cf. A003666.

1, 1, 1, 1, 2, 3, 4, 5, 7, 8, 11, 13, 17, 20, 25, 30, 38, 44, 54, 63, 77, 90, 107, 124, 148, 171, 202, 231, 271, 310, 360, 412, 477, 542, 622, 705, 809, 915, 1042, 1175, 1335, 1501, 1699, 1905, 2148, 2403, 2702, 3018, 3383, 3768, 4212, 4682, 5223, 5794, 6445

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OFFSET

0,5

LINKS

Table of n, a(n) for n=0..54.

Eric Weisstein's World of Mathematics, Ulam Sequence

Wikipedia, Ulam number

Index entries for Ulam numbers

EXAMPLE

The first terms of A003666 are 1, 4, 5, 6, 7, 8, 10, 16, 18, 19, ...

a(7) = #{7, 6+1, 5+1+1, 4+1+1+1, 7x1} = 5;

a(8) = #{8, 7+1, 6+1+1, 5+1+1+1, 4+4, 4+1+1+1+1, 8x1} = 7;