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Partial sums of A003214.
0

%I #2 Mar 30 2012 18:40:51

%S 1,2,4,7,13,23,43,80,156,308,628,1300,2754,5908,12867,28306,62914,

%T 140902,317887,721397,1646080,3773415,8686867,20072822,46541053,

%U 108241285,252447554,590284775,1383498325,3249679480,7648547152

%N Partial sums of A003214.

%C Partial sums of number of binary forests with n nodes. The subsequence of primes in this partial sum begins: 2, 7, 13, 23, 43, 317887, 721397, 238855831229, 154308201825571245947273 = a(65).

%F a(n) = SUM[i=0..n] A003214(i).

%e a(34) = 1 + 1 + 2 + 3 + 6 + 10 + 20 + 37 + 76 + 152 + 320 + 672 + 1454 + 3154 + 6959 + 15439 + 34608 + 77988 + 176985 + 403510 + 924683 + 2127335 + 4913452 + 11385955 + 26468231 + 61700232 + 144206269 + 337837221 + 793213550 + 1866181155 + 4398867672 + 10387045476 + 24567374217 + 58196129468 + 138056734916 = 238855831229 is prime,

%Y Cf. A003214.

%K easy,nonn

%O 0,2

%A _Jonathan Vos Post_, Mar 22 2010