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Search: id:A110207
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| A110207 |
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a(n) = sum of cubes of numbers < 2^n having exactly [n/2]+1 ones in their binary expansion. |
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+0
3
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| 1, 27, 368, 6615, 88536, 1449198, 20078192, 320944275, 4584724120, 72867715074, 1064153845776, 16896536592390, 250629464211504, 3980364331323996, 59709362473177824, 948742244639103915, 14352114907032903000
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(n) equals the largest term in row n of triangle A110205.
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FORMULA
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a(n) = (8^n-1)/7*C(n-3, [n/2]) + ((2^n-1)*(4^n-1)-(8^n-1)/7)*C(n-3, [n/2]-1) + (2^n-1)^3*C(n-3, [n/2]-2).
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PROGRAM
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(PARI) {a(n)=(8^n-1)/7*binomial(n-3, n\2)+((2^n-1)*(4^n-1)-(8^n-1)/7)*binomial(n-3, n\2-1) +(2^n-1)^3*binomial(n-3, n\2-2)}
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CROSSREFS
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Cf. A110205 (triangle), A110206 (row sums).
Sequence in context: A022622 A030648 A042410 this_sequence A010979 A022591 A000535
Adjacent sequences: A110204 A110205 A110206 this_sequence A110208 A110209 A110210
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Jul 16 2005
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