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A255186
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27-gonal numbers: a(n) = n*(25*n-23)/2.
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8
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0, 1, 27, 78, 154, 255, 381, 532, 708, 909, 1135, 1386, 1662, 1963, 2289, 2640, 3016, 3417, 3843, 4294, 4770, 5271, 5797, 6348, 6924, 7525, 8151, 8802, 9478, 10179, 10905, 11656, 12432, 13233, 14059, 14910, 15786, 16687, 17613, 18564, 19540
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OFFSET
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0,3
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COMMENTS
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REFERENCES
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E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 6 (25th row of the table).
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LINKS
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FORMULA
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G.f.: x*(-1 - 24*x)/(-1 + x)^3.
Product_{n>=2} (1 - 1/a(n)) = 25/27. - Amiram Eldar, Jan 22 2021
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MATHEMATICA
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Table[n (25 n - 23)/2, {n, 40}]
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PROG
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CROSSREFS
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Cf. similar sequences listed in A255184.
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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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