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A258622 a(1) = 2, a(n+1) = a(n) * (1 + n + a(n))/n. 0
2, 8, 44, 704, 124784, 3114359072, 1616538741858202448, 373313929132642872042128187516973184, 17420411210556488056172048238850552742971470265342499948186222078482064 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The next term has 139 digits.

LINKS

Table of n, a(n) for n=1..9.

StackExchange - Mathematics, Quadratic Recurrence Relation (sequence b(n) in the reference).

FORMULA

a(n) ~ n * c^(2^n), where c = 1.36534926036757464312824443040683531215776134381623126072...

MATHEMATICA

FoldList[#1*(1+#2+#1)/#2&, 2, Range@8] (* Ivan N. Ianakiev, Jun 06 2015 *)

PROG

(Maxima) a(n) := if n = 1 then 2 else a(n-1)*(n+a(n-1))/(n-1) $

makelist(a(n), n, 1, 12); Emanuele Munarini, Mar 23 2017

CROSSREFS

Sequence in context: A002833 A139015 A197996 * A290442 A316367 A308599

Adjacent sequences:  A258619 A258620 A258621 * A258623 A258624 A258625

KEYWORD

nonn

AUTHOR

Vaclav Kotesovec, Jun 06 2015

STATUS

approved

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Last modified February 25 22:37 EST 2021. Contains 341618 sequences. (Running on oeis4.)