%I #11 Oct 07 2017 22:32:54
%S 4,4,6,20,4845,22201944189472719,
%T 166346452361171550314824489703019621783015631944522524541726975745905615181160551330988078433117
%N A binomial recursion sequence: a(n+1) = binomial(a(n),n), with a(1) = 4.
%C a(8) is:
%C 699301187738697776955234590818575878858497870436943950335371702267592105356658
%C 849941404678768037675247402565958747959976067293704659262352355225014691708927
%C 778552892641086343071274181444416049073520682688565978919033071721714880653653
%C 080309872598715536025092978123435527211585005389271350498723935289464449420805
%C 795571832413526658955115512510611494293919617563498533091225832128243546205605
%C 992399467856781652450135524637534848361445349052823349129955310671992962375769
%C 922037205735947982909072338647248893042158639365515004077074834659222711212403
%C 575797324146436716175464082981330742529857175516323162599993277609188166949854
%C 918220220568926227236394740277576705068
%C The sequence continues to grow quite rapidly thereafter.
%C a(1) = 4 is the smallest meaningful seed for the sequence; if we start with a(1) = 3, the sequence is finite: 3,3,1.
%t a[1] = 4; a[n_] := a[n] = Binomial[a[n - 1], n - 1];
%t Table[a[n], {n, 1, 8}]
%K nonn
%O 1,1
%A _Roger L. Bagula_ and _Gary W. Adamson_, Oct 23 2008
%E Edited by _Franklin T. Adams-Watters_, Oct 05 2017