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URL: https://oeis.org/A047539

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A047539
Numbers that are congruent to {2, 4, 7} mod 8.
0
2, 4, 7, 10, 12, 15, 18, 20, 23, 26, 28, 31, 34, 36, 39, 42, 44, 47, 50, 52, 55, 58, 60, 63, 66, 68, 71, 74, 76, 79, 82, 84, 87, 90, 92, 95, 98, 100, 103, 106, 108, 111, 114, 116, 119, 122, 124, 127, 130, 132, 135, 138, 140, 143, 146, 148, 151, 154, 156, 159
OFFSET
1,1
COMMENTS
a(n) is also the irregularity strength of the (n-1)-Cameron graph. - Eric W. Weisstein, Sep 02 2025
LINKS
Eric Weisstein's World of Mathematics, Cameron Graph.
Eric Weisstein's World of Mathematics, Irregularity Strength.
FORMULA
a(n) = floor((8*n-2)/3). - Gary Detlefs, Mar 13 2010
From Wesley Ivan Hurt, Jun 09 2016: (Start)
G.f.: x*(2+2*x+3*x^2+x^3)/((x-1)^2*(1+x+x^2)).
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = (24*n-9+2*sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-1, a(3k-1) = 8k-4, a(3k-2) = 8k-6. (End)
MAPLE
seq(floor((8*n-3)/3), n=1..51); # Gary Detlefs, Mar 07 2010
MATHEMATICA
Table[Floor[(8 n - 2)/3], {n, 50}] (* Wesley Ivan Hurt, Feb 15 2014 *)
LinearRecurrence[{1, 0, 1, -1}, {2, 4, 7, 10}, 80] (* Harvey P. Dale, Feb 02 2025 *)
Table[(24 n - 9 + 2 Sqrt[3] Sin[2 n Pi/3])/9, {n, 20}] (* Eric W. Weisstein, Sep 02 2025 *)
CoefficientList[Series[(2 + 2 x + 3 x^2 + x^3)/((-1 + x)^2 (1 + x + x^2)), {x, 0, 20}], x] (* Eric W. Weisstein, Sep 02 2025 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [2, 4, 7]]; // Wesley Ivan Hurt, Jun 09 2016
CROSSREFS
Sequence in context: A285968 A218772 A057843 * A190521 A186224 A008062
KEYWORD
nonn,easy
STATUS
approved