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A199120 Number of partitions of n into terms of (1,4)-Ulam sequence, cf. A003666. 6
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,5
LINKS
Eric Weisstein's World of Mathematics, Ulam Sequence
Wikipedia, Ulam number
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;
a(9) = #{8+1, 7+1+1, 6+1+1+1, 5+4, 5+1+1+1+1, 4+4+1, 4+5x1, 9x1} = 8.
PROG
(Haskell)
a199120 = p a003666_list where
p _ 0 = 1
p us'@(u:us) m | m < u = 0
| otherwise = p us' (m - u) + p us m
CROSSREFS
Sequence in context: A080655 A367358 A354816 * A118083 A241093 A116470
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Nov 03 2011
STATUS
approved

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Last modified May 23 09:20 EDT 2024. Contains 372760 sequences. (Running on oeis4.)