A302576 Numbers k such that k/10 + 1 is a square.
-10, 0, 30, 80, 150, 240, 350, 480, 630, 800, 990, 1200, 1430, 1680, 1950, 2240, 2550, 2880, 3230, 3600, 3990, 4400, 4830, 5280, 5750, 6240, 6750, 7280, 7830, 8400, 8990, 9600, 10230, 10880, 11550, 12240, 12950, 13680, 14430, 15200, 15990, 16800, 17630, 18480, 19350, 20240
Offset: 1
Links
- Bruno Berselli, Table of n, a(n) for n = 1..1000
- Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
Crossrefs
After -10, subsequence of A174133 because a(n) = ((n-1)^2-1)*(3^2+1).
Programs
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GAP
List([1..50], n -> 10*n*(n-2));
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Julia
[10*n*(n-2) for n in 1:50] |> println
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Magma
[10*n*(n-2): n in [1..50]];
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Mathematica
Table[10 n (n - 2), {n, 1, 50}] -
Maxima
makelist(10*n*(n-2), n, 1, 50);
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PARI
vector(50, n, nn; 10*n*(n-2))
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Python
[10*n*(n-2) for n in range(1, 50)]
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Sage
[10*n*(n-2) for n in (1..50)]
Formula
O.g.f.: -10*x*(1 - 3*x)/(1 - x)^3.
E.g.f.: -10*x*(1 - x)*exp(x).
a(n) = a(2-n).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
a(n) = 10*n*(n - 2) = 10*A067998(n).
a(n) = A033583(n-1) - 10. - Altug Alkan, Apr 10 2018
Comments