This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A101702 #19 Jun 05 2025 23:32:03
%S A101702 1,2,541,52100,58504,66410,430000,863180,8601400,17927300,27927300,
%T A101702 31000000,665100000,3715000000,6739630000,11000000000,21000000000,
%U A101702 53100000000,70858000000,79637300000,451000000000,1715000000000,2715000000000,48304000000000,340000000000000,5520000000000000
%N A101702 Numbers m such that the sum of the factorials of their digits is equal to the reversal of m.
%C A101702 If s=sum of the factorials of digits of m & reversal(m) >= s then 10^(reversal(m) - s)*m is in the sequence. Example m=23; s = 2! + 3!; reversal(23) - s = 24 & 23*10^24 is in the sequence. So this sequence is infinite because there exist infinitely many numbers m such that reversal(m) > s. If m is a k-digit term of this sequence and the first digit of m is 1 then 10^(k-1) + m is also in the sequence. Examples: m=1 so 10^(1-1) + 1 = 2 is in the sequence, m=17927300 so 10^7 + 17927300 = 27927300 is in the sequence. If m > 5 then 10 divides a(m). If 10 doesn't divide a(m) then the reversal of m is in the sequence A014080, so all terms of A014080 are: reversal(1), reversal(2), reversal(541) & reversal(58504).
%e A101702 665100000 is in the sequence because reversal(665100000) = 1566 = 6! + 6! + 5! + 1! + 0! + 0! + 0! + 0! + 0!.
%t A101702 Do[h = IntegerDigits[n]; l = Length[h]; If[FromDigits[Reverse[IntegerDigits[n]]] == Sum[h[[k]]!, {k, l}], Print[n]], {n, 10^9}]
%Y A101702 Cf. A014080, A049529, A101697.
%K A101702 base,nonn
%O A101702 1,2
%A A101702 _Farideh Firoozbakht_, Dec 24 2004
%E A101702 More terms from _Donovan Johnson_, Feb 26 2008