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A022265
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a(n) = n*(7*n + 1)/2.
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14
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0, 4, 15, 33, 58, 90, 129, 175, 228, 288, 355, 429, 510, 598, 693, 795, 904, 1020, 1143, 1273, 1410, 1554, 1705, 1863, 2028, 2200, 2379, 2565, 2758, 2958, 3165, 3379, 3600, 3828, 4063, 4305, 4554, 4810
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OFFSET
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0,2
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COMMENTS
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For n >= 4, a(n) is the sum of the numbers appearing in the 4th row of an n X n square array whose elements are the numbers from 1..n^2, listed in increasing order by rows. - Wesley Ivan Hurt, May 17 2021
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LINKS
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FORMULA
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a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) with a(0)=0, a(1)=4, a(2)=15. - Philippe Deléham, Mar 26 2013
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EXAMPLE
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After 0:
4 = -(1) + (2 + 3).
15 = -(1 + 2) + (3 + 4 + 5 + 6).
33 = -(1 + 2 + 3) + (4 + 5 + 6 + 7 + 8 + 9).
58 = -(1 + 2 + 3 + 4) + (5 + 6 + 7 + 8 + 9 + 10 + 11 + 12). (End)
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MAPLE
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seq(binomial(6*n+1, 2)/3-binomial(5*n+1, 2)/5, n=0..42); # Zerinvary Lajos, Jan 21 2007
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MATHEMATICA
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LinearRecurrence[{3, -3, 1}, {0, 4, 15}, 40] (* Harvey P. Dale, Oct 09 2018 *)
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PROG
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CROSSREFS
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Cf. similar sequences listed in A022289.
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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