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A084323 Fixed points reached when prime-factor-concatenation function [A084317] is started at n!. 0

%I

%S 0,2,23,23,547,547,2357,2357,2357,2357,4359293547691,4359293547691,

%T 325798243129564339,325798243129564339,325798243129564339,

%U 325798243129564339,3947306373286437248759663633906484193454376823

%N Fixed points reached when prime-factor-concatenation function [A084317] is started at n!.

%F a(n)=A084318[A000142(n)]=A084318[n! ]

%e n=11: 11!=256.81.25.7.11; a(11)=iter[concatenate[{2,3,5,7,11}]] =A084318[39916800]; the list of iteration:

%e {39916800, 235711, 7151223, 34495309, 41841349, 1116722777, 1958774883, 313113444469, 744730492067, 4359293547691}

%e at each step the ordered prime factors of previous term are concatenated.

%t ffi[x_] := Flatten[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] q[x_] := Apply[Times, Table[Prime[w], {w, 1, x}]] lf[x_] := Length[FactorInteger[x]] nd[x_, y_] := 10*x+y tn[x_] := Fold[nd, 0, x] coc[x_] := Fold[nd, 0, Flatten[IntegerDigits[ba[x]], 1]] Table[FixedPoint[coc, q[w]], {w, 1, 7}]

%Y Cf. A001405, A084317, A084318, A084322.

%K base,nonn

%O 1,2

%A _Labos Elemer_, Jun 20 2003

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Last modified August 20 15:13 EDT 2019. Contains 326152 sequences. (Running on oeis4.)