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 A085036 a(n) = (5*n+2)*(5*n+7). 0

%I

%S 14,84,204,374,594,864,1184,1554,1974,2444,2964,3534,4154,4824,5544,

%T 6314,7134,8004,8924,9894,10914,11984,13104,14274,15494,16764,18084,

%U 19454,20874,22344,23864,25434,27054,28724,30444,32214,34034,35904,37824,39794,41814

%N a(n) = (5*n+2)*(5*n+7).

%C 1 = 2/7 + Sum(n=1,inf.,25/a(n)) = 2/7 + 25/84 + 25/204 + 25/374 + 25/594...+...; with partial sums: 2/7, 7/12, 12/17, 17/22...(5n+2)/(5n+7)...==>1

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).

%F 25n^2 + 45n + 14.

%o (PARI) a(n)=(5*n+2)*(5*n+7) \\ _Charles R Greathouse IV_, Jun 17 2017

%K nonn,easy

%O 0,1

%A _Gary W. Adamson_, Jun 19 2003

%E Corrected by Douglas McNeil and _Charles R Greathouse IV_, Aug 31 2010

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Last modified December 8 02:30 EST 2019. Contains 329850 sequences. (Running on oeis4.)