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A120297
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Sum of all matrix elements of n X n matrix M(i,j) = Fibonacci(i+j-1).
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4
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1, 5, 20, 65, 193, 544, 1489, 4005, 10660, 28193, 74273, 195200, 512257, 1343077, 3519412, 9219105, 24144289, 63224096, 165544721, 433437125, 1134810436, 2971065025, 7778499265, 20364618240, 53315655553, 139582833989
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OFFSET
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1,2
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COMMENTS
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p^2 divides a(p-1) for p = 5, 11, 19, 29, 31, 41, 59, 61, 71, ... = A038872 (Primes congruent to {0, 1, 4} mod 5), also odd primes p such that where 5 is a square mod p. All squared prime divisors of a(n) also belong to A038872.
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LINKS
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FORMULA
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a(n) = Sum_{j=1..n} Sum_{i=1..n} Fibonacci(i+j-1).
a(n) = Fibonacci(2*n+3) - 2*Fibonacci(n+3) + 2. - Vladeta Jovovic, Jul 21 2006
G.f.: (1 - x^3 + 2*x^2)/((x-1)*(x^2 + x - 1)*(x^2 - 3*x + 1)). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 14 2009
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EXAMPLE
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Matrix begins:
1 1 2 3 5
1 2 3 5 8
2 3 5 8 13
3 5 8 13 21
5 8 13 21 34
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MATHEMATICA
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Table[Sum[Sum[Fibonacci[i+j-1], {i, 1, n}], {j, 1, n}], {n, 1, 50}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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