The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A007439

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A007439

Number of planted trees: all sub-rooted trees from any node are identical; non-root, non-leaf nodes an even distance from the root are of degree 2.
(history; published version)

#28 by Jon E. Schoenfield at Fri Dec 17 11:11:53 EST 2021

STATUS

editing

approved

#27 by Jon E. Schoenfield at Fri Dec 17 11:11:51 EST 2021

AUTHOR

N. J. A. Sloane.

EXTENSIONS

New description from Christian G. Bower, Oct 15 1998.

STATUS

approved

editing

#26 by Alois P. Heinz at Thu May 09 18:33:30 EDT 2019

STATUS

proposed

approved

#25 by Ilya Gutkovskiy at Thu May 09 17:14:38 EDT 2019

STATUS

editing

proposed

#24 by Ilya Gutkovskiy at Thu May 09 16:58:39 EDT 2019

FORMULA

G.f. A(x) satisfies: A(x) = x + x^2 * (1 + A(x) + A(x^2) + A(x^3) + ...). - Ilya Gutkovskiy, May 09 2019

CROSSREFS

Cf. A027750.

STATUS

approved

editing

#23 by Reinhard Zumkeller at Sat Dec 20 08:13:10 EST 2014

STATUS

editing

approved

#22 by Reinhard Zumkeller at Sat Dec 20 08:03:09 EST 2014

PROG

(Haskell)

a007439 n = a007439_list !! (n-1)

a007439_list = 1 : 1 : f 2 where

f x = (sum $ map a007439 $ a027750_row (x - 1)) : f (x + 1)

-- Reinhard Zumkeller, Dec 20 2014

CROSSREFS

Cf. A027750.

STATUS

approved

editing

#21 by Reinhard Zumkeller at Mon Jan 27 04:25:50 EST 2014

STATUS

editing

approved

#20 by Reinhard Zumkeller at Mon Jan 27 04:21:41 EST 2014

KEYWORD

nonn,nice,eigen,look

STATUS

approved

editing

#19 by Bruno Berselli at Wed May 15 08:40:11 EDT 2013

STATUS

proposed

approved