%I #21 Apr 03 2023 10:36:13
%S 2,3,5,7,8,11,15,30,42,58,61,64,74,77,432,500,520,601,640,675,717,888,
%T 910,940,943,950,951,957,1210,2100
%N Numbers n such that n*reversal(n)! - 1 is prime.
%H Chris K. Caldwell and G. L. Honaker, Jr., <a href="https://t5k.org/curios/page.php?short=943">Prime Curios! 943</a>
%e n=15 : reversal(15)=51. (15*51!-1) = 23266781299310734203363645247039548165948895800254791679999999999999 which is prime. Hence, 15 is in sequence.
%p with(StringTools):KD:= proc() local a;a:=n*parse(Reverse(convert(n,string)))!-1; if isprime(a) then RETURN (n) fi: end: seq(KD(), n=1..1000);
%p with(StringTools):KD:=proc()local n,a,c; c:=1; for n from 1 to 1000 do;a:=n*parse(Reverse(convert(n,string)))!-1;if isprime(a) then lprint(c,n); c:=c+1; fi;od; end: KD();
%t Select[Range[80],PrimeQ[#*IntegerReverse[#]!-1]&] (* The program generates the first 14 terms in the sequence. To generate more, increase the Range constant but the program may take a long time to run. *) (* _Harvey P. Dale_, Jan 31 2022 *)
%K nonn,base
%O 1,1
%A _K. D. Bajpai_, Jul 22 2013
%E a(29)-a(30) from _Giovanni Resta_, Jul 22 2013