A108065 - OEIS

A108065

Numbers n such that DENEAT(n!) is prime, where DENEAT(n) = concatenate number of even digits in n, number of odd digits and total number of digits.

%I #6 Dec 15 2017 17:36:48

%S 1,2,3,10,15,29,35,39,51,65,167,185,198,250,282,325,366,368,382,396,

%T 400,403,450,453,509,574,575,590,598,601,699,720,759,764,788,791,797,

%U 817,824,860,863,865,867,877,901,909,911,913,930,936,1066,1068,1081,1145

%N Numbers n such that DENEAT(n!) is prime, where DENEAT(n) = concatenate number of even digits in n, number of odd digits and total number of digits.

%H Harvey P. Dale, <a href="/A108065/b108065.txt">Table of n, a(n) for n = 1..1000</a>

%e 10 is in the sequence because 10! = 3628800 has 6 even digits, 1

%e odd digit and 7 total digits, yielding the prime 617.

%t eotQ[n_]:=Module[{idnf=IntegerDigits[n!],len,ev,od},len=Length[idnf];ev= Count[ idnf,_?EvenQ];od=Count[idnf,_?OddQ];PrimeQ[FromDigits[ Flatten[ IntegerDigits/@ Join[{ev,od,len}]]]]]; Select[Range[1200],eotQ] (* _Harvey P. Dale_, Jul 05 2017 *)

%Y Cf. A073053.

%K base,nonn

%O 1,2

%A _Jason Earls_, Jun 03 2005