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A345735
A prime-generating quasipolynomial: a(n) = 6*floor(n^2/4) + 17.
0
17, 17, 23, 29, 41, 53, 71, 89, 113, 137, 167, 197, 233, 269, 311, 353, 401, 449, 503, 557, 617, 677, 743, 809, 881, 953, 1031, 1109, 1193, 1277, 1367, 1457, 1553, 1649, 1751, 1853, 1961, 2069, 2183, 2297, 2417, 2537, 2663, 2789, 2921, 3053, 3191, 3329, 3473, 3617
OFFSET
0,1
COMMENTS
Fontebasso only claims that the terms are prime from 0 to 22, but in fact a(23)..a(30) are all prime as well. The first composite term is a(31) = 1457 = 31*47.
LINKS
FORMULA
a(n) = A319127(n+1) + 17 = 6*A002620(n) + 17. - Omar E. Pol, Jul 12 2021
G.f.: (17*x^3-11*x^2-17*x+17)/((x+1)*(1-x)^3). - Alois P. Heinz, Jul 12 2021
E.g.f.: ((34 + 3*x + 3*x^2)*cosh(x) + (31 + 3*x + 3*x^2)*sinh(x))/2. - Stefano Spezia, Jul 13 2021
PROG
(PARI) a(n)=n^2\4*6+17
CROSSREFS
Sequence in context: A216436 A060360 A081702 * A238235 A333152 A040273
KEYWORD
nonn,easy
AUTHOR
STATUS
approved