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A152955
Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) has height 1.
8
1, 3, 5, 7, 11, 13, 15, 17, 19, 21, 23, 29, 31, 33, 35, 37, 39, 41, 43, 47, 51, 53, 55, 57, 59, 61, 65, 67, 69, 71, 73, 77, 79, 83, 85, 87, 89, 91, 93, 95, 97, 101, 103, 107, 109, 111, 113, 115, 119, 123, 127, 129, 131, 133, 137, 139, 141, 143, 145, 149, 151, 155, 157
OFFSET
1,2
COMMENTS
The height of a polynomial is the maximum of the absolute value of its coefficients. Polynomials of height 1 are also called flat polynomials. This sequence includes prime (first order) and semiprime (second order) n, as well as third-order (A117223), fourth-order (A117318) and higher-order n.
PROG
(PARI) is(n)=issquarefree(n) && n%2 && vecmax(abs(Vec(polcyclo(n))))==1 \\ Charles R Greathouse IV, Nov 05 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Dec 16 2008
STATUS
approved