A174566 - OEIS

A174566

Partial sums of A003214.

1, 2, 4, 7, 13, 23, 43, 80, 156, 308, 628, 1300, 2754, 5908, 12867, 28306, 62914, 140902, 317887, 721397, 1646080, 3773415, 8686867, 20072822, 46541053, 108241285, 252447554, 590284775, 1383498325, 3249679480, 7648547152

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OFFSET

0,2

COMMENTS

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).

LINKS

Table of n, a(n) for n=0..30.

FORMULA

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

EXAMPLE

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,

CROSSREFS

Cf. A003214.

Sequence in context: A054163 A036256 A093629 * A018182 A005595 A347025

Adjacent sequences: A174563 A174564 A174565 * A174567 A174568 A174569

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Mar 22 2010

STATUS

approved