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A174566 Partial sums of A003214. 0
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 (list; graph; refs; listen; history; text; internal format)
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 A296689

Adjacent sequences:  A174563 A174564 A174565 * A174567 A174568 A174569

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Mar 22 2010

STATUS

approved

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Last modified September 25 10:39 EDT 2021. Contains 347654 sequences. (Running on oeis4.)