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A347788
Number of compositions (ordered partitions) of n into at most 2 nonprime parts.
6
1, 1, 1, 0, 1, 2, 1, 2, 2, 3, 5, 2, 4, 4, 5, 5, 8, 4, 8, 6, 8, 7, 11, 6, 12, 9, 13, 9, 14, 10, 16, 12, 14, 13, 19, 13, 22, 14, 17, 17, 22, 16, 24, 18, 22, 19, 25, 18, 28, 21, 28, 21, 28, 22, 32, 25, 30, 25, 33, 26, 38, 28, 31, 29, 38, 29, 42, 30, 34, 33, 42
OFFSET
0,6
LINKS
MATHEMATICA
Table[Length@Flatten[Permutations/@IntegerPartitions[n, 2, Select[Range@n, !PrimeQ@#&]], 1], {n, 0, 70}] (* Giorgos Kalogeropoulos, Sep 13 2021 *)
PROG
(PARI) A347788(n) = if(n<2, 1, !isprime(n)+sum(k=1, n-1, !(isprime(k)+isprime(n-k)))); \\ Antti Karttunen, Nov 25 2022
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 13 2021
STATUS
approved