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A086765 Number of positive coefficients in n-th cyclotomic polynomial. 5
1, 2, 3, 2, 5, 2, 7, 2, 3, 3, 11, 2, 13, 4, 4, 2, 17, 2, 19, 3, 5, 6, 23, 2, 5, 7, 3, 4, 29, 4, 31, 2, 8, 9, 9, 2, 37, 10, 9, 3, 41, 5, 43, 6, 4, 12, 47, 2, 7, 3, 12, 7, 53, 2, 9, 4, 13, 15, 59, 4, 61, 16, 5, 2, 16, 8, 67, 9, 16, 9, 71, 2, 73, 19, 4, 10, 16, 9, 79, 3, 3, 21, 83, 5, 21, 22, 20, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

See A051664

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

FORMULA

If n = p^m is a prime power then a(n) = p.

EXAMPLE

The 1st cyclotomic polynomial is -1+1*x, which has 1 positive coefficient.

The 2nd cyclotomic polynomial is 1+1*x, which has 2 positive coefficients.

The 4th cyclotomic polynomial s 1+1*x^2, which has 2 positive coefficients.

MATHEMATICA

Table[Count[CoefficientList[Cyclotomic[n, x], x], _?(#>0&)], {n, 0, 100}]

CROSSREFS

Cf. A007947.

Cf. A051664 (number of nonzero terms in n-th cyclotomic polynomial).

Sequence in context: A273288 A080210 A126594 * A079868 A280697 A088444

Adjacent sequences:  A086762 A086763 A086764 * A086766 A086767 A086768

KEYWORD

nonn

AUTHOR

Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 02 2003

EXTENSIONS

More terms from T. D. Noe, Aug 08 2003

STATUS

approved

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Last modified September 19 11:06 EDT 2019. Contains 327192 sequences. (Running on oeis4.)