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A199122 Number of partitions of n into terms of (2,3)-Ulam sequence, cf. A001857. 6
1, 0, 1, 1, 1, 2, 2, 3, 4, 5, 6, 7, 9, 11, 14, 16, 20, 23, 29, 33, 39, 47, 54, 64, 75, 86, 101, 117, 135, 155, 179, 204, 236, 268, 306, 349, 397, 450, 511, 577, 653, 736, 831, 934, 1050, 1179, 1322, 1478, 1657, 1848, 2065, 2302, 2562, 2852, 3172, 3518, 3909 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Table of n, a(n) for n=0..56.

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, ...

a(10) = #{8+2, 7+3, 5+5, 5+3+2, 3+3+2+2, 2+2+2+2+2} = 6;

a(11) = #{9+2, 8+3, 7+2+2, 5+3+3, 5+2+2+2, 3+3+3+2, 3+2+2+2+2} = 7;

a(12) = #{9+3, 8+2+2, 7+5, 7+3+2, 5+5+2, 5+3+2+2, 3+3+3+3, 3+3+2+2+2, 6x2} = 9.

PROG

(Haskell)

a199122 = p a001857_list where

   p _ 0 = 1

   p us'@(u:us) m | m < u     = 0

                  | otherwise = p us' (m - u) + p us m

CROSSREFS

Cf. A000607; A199123, A199016, A199118, A199120.

Sequence in context: A014215 A067014 A096791 * A086740 A120161 A100665

Adjacent sequences:  A199119 A199120 A199121 * A199123 A199124 A199125

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Nov 03 2011

STATUS

approved

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Last modified May 26 02:56 EDT 2020. Contains 334613 sequences. (Running on oeis4.)