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A354343 Number of distinct sums of n complex 6th power roots of unity. 1
1, 6, 19, 37, 61, 91, 127, 169, 217, 271, 331, 397, 469, 547, 631, 721, 817, 919, 1027, 1141, 1261, 1387, 1519, 1657, 1801, 1951, 2107, 2269, 2437, 2611, 2791, 2977, 3169, 3367, 3571, 3781, 3997, 4219, 4447, 4681, 4921, 5167, 5419, 5677, 5941, 6211, 6487, 6769, 7057, 7351, 7651, 7957 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
For n >= 2, a(n) = 3*n^2 + 3*n + 1 = A003215(n).
For n >= 5, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
G.f. (1 + 3*x + 4*x^2 - 3*x^3 + x^4) / (1 - x)^3.
PROG
(PARI) a(n)=if(n==1, 6, 3*n*(n+1)+1) \\ Charles R Greathouse IV, Aug 15 2022
CROSSREFS
Same as A003215 except for a(1) = 6.
Row 6 of A299807.
Sequence in context: A031014 A010899 A090381 * A106398 A179986 A054567
KEYWORD
nonn,easy
AUTHOR
Max Alekseyev, Aug 15 2022
STATUS
approved

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Last modified March 28 04:13 EDT 2024. Contains 371235 sequences. (Running on oeis4.)