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A341136 Number of ways to write n as an ordered sum of 7 prime powers (including 1). 7
1, 7, 28, 84, 210, 455, 882, 1569, 2611, 4116, 6223, 9093, 12901, 17822, 24053, 31759, 41132, 52367, 65702, 81326, 99526, 120471, 144417, 171493, 201985, 235963, 273889, 315805, 362181, 413021, 468888, 529466, 595770, 667541, 745899, 830473, 922866, 1021832, 1129499 (list; graph; refs; listen; history; text; internal format)
OFFSET

7,2

LINKS

Table of n, a(n) for n=7..45.

MAPLE

q:= proc(n) option remember; nops(ifactors(n)[2])<2 end:

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

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

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

    end:

a:= n-> b(n, 7):

seq(a(n), n=7..45);  # Alois P. Heinz, Feb 05 2021

MATHEMATICA

nmax = 45; CoefficientList[Series[Sum[Boole[PrimePowerQ[k] || k == 1] x^k, {k, 1, nmax}]^7, {x, 0, nmax}], x] // Drop[#, 7] &

CROSSREFS

Cf. A000961, A010055, A282062, A282064, A341125, A341133, A341134, A341135, A341137, A341138, A341139.

Sequence in context: A162595 A073363 A247608 * A166322 A008499 A049018

Adjacent sequences:  A341133 A341134 A341135 * A341137 A341138 A341139

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Feb 05 2021

STATUS

approved

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Last modified May 8 15:54 EDT 2021. Contains 343666 sequences. (Running on oeis4.)