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A341480 Number of ways to write n as an ordered sum of 3 nonprime numbers. 8
1, 0, 0, 3, 0, 3, 3, 3, 9, 4, 9, 12, 12, 15, 21, 19, 27, 30, 30, 39, 42, 46, 54, 60, 61, 75, 72, 91, 90, 108, 99, 129, 123, 142, 147, 168, 156, 201, 180, 217, 213, 246, 235, 279, 255, 304, 297, 336, 327, 375, 342, 412, 390, 447, 423, 492, 453, 529, 507, 573, 538, 630, 579 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,4

LINKS

Robert Israel, Table of n, a(n) for n = 3..10000

FORMULA

G.f. g(x)^3 where g(x) is the G.f. of A005171.

MAPLE

b:= proc(n, t) option remember;

      `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add(

      `if`(isprime(j), 0, b(n-j, t-1)), j=1..n)))

    end:

a:= n-> b(n, 3):

seq(a(n), n=3..65);  # Alois P. Heinz, Feb 13 2021

MATHEMATICA

nmax = 65; CoefficientList[Series[Sum[Boole[!PrimeQ[k]] x^k, {k, 1, nmax}]^3, {x, 0, nmax}], x] // Drop[#, 3] &

CROSSREFS

Cf. A005171, A018252, A052284, A076608, A098238, A341408, A341461, A341481, A341482, A341483, A341484, A341485, A341486.

Sequence in context: A288571 A270028 A167223 * A261922 A078907 A282135

Adjacent sequences:  A341477 A341478 A341479 * A341481 A341482 A341483

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Feb 13 2021

STATUS

approved

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Last modified June 16 21:55 EDT 2021. Contains 345080 sequences. (Running on oeis4.)