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A358206
Number of ways of making change for n cents using coins of 1, 2, 4, 10 and 20 cents.
0
1, 1, 2, 2, 4, 4, 6, 6, 9, 9, 13, 13, 18, 18, 24, 24, 31, 31, 39, 39, 50, 50, 62, 62, 77, 77, 93, 93, 112, 112, 134, 134, 159, 159, 187, 187, 218, 218, 252, 252, 292, 292, 335, 335, 384, 384, 436, 436, 494, 494, 558, 558, 628, 628, 704, 704, 786, 786, 874, 874, 972, 972
OFFSET
0,3
COMMENTS
Number of ways of making change for 50n Colombian pesos using coins of 50, 100, 200, 500 and 1000 pesos.
Number of partitions of n into parts 1,2,4,10 and 20.
LINKS
Index entries for linear recurrences with constant coefficients, signature (1, 1, -1, 1, -1, -1, 1, 0, 0, 1, -1, -1, 1, -1, 1, 1, -1, 0, 0, 1, -1, -1, 1, -1, 1, 1, -1, 0, 0, -1, 1, 1, -1, 1, -1, -1, 1).
FORMULA
G.f.: 1/((1 - x) (1 - x^2) (1 - x^4) (1 - x^10) (1 - x^20)).
a(n) = A000064(floor(n/2)).
a(n) ~ n^4/38400.
EXAMPLE
a(5)=4 counts the ways of making change for 5 cents, these are (1,1,1,1,1), (1,1,1,2), (1,2,2), (1,4).
MATHEMATICA
A[x_]:=1/((1 - x) (1 - x^2) (1 - x^4) (1 - x^10) (1 - x^20));
a[n_]:=SeriesCoefficient[A[x], {x, 0, n}]
CROSSREFS
Sequence in context: A029010 A060027 A001362 * A001310 A328422 A029009
KEYWORD
nonn,easy
AUTHOR
Daniel Checa, Nov 03 2022
STATUS
approved