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 A351896 #9 Feb 26 2022 10:11:04 %S A351896 71,743,791,839,862,910,983,1031,1079,1102,1150,1223,1271,1319,1342, %T A351896 1390,1583,1631,1823,1871,2063,2111,2183,2231,2279,2302,2350,2423, %U A351896 2471,2519,2542,2590,2663,2711,2759,2782,2830,3023,3071,3263,3311,3503,3551,3623,3671,3719 %N A351896 Numbers k such that k and k+2 both have an equal number of odd and even digits in their factorial-base representations. %H A351896 Amiram Eldar, <a href="/A351896/b351896.txt">Table of n, a(n) for n = 1..10000</a> %H A351896 Wikipedia, <a href="https://en.wikipedia.org/wiki/Factorial_number_system">Factorial number system</a>. %H A351896 <a href="/index/Fa#facbase">Index entries for sequences related to factorial base representation</a>. %e A351896 71 is a term since the factorial-base representations of 71 and 73 are 2321 and 3001, respectively, and both have 2 odd digits and 2 even digits. %t A351896 max = 7; fctBaseDigits[n_] := IntegerDigits[n, MixedRadix[Range[max, 2, -1]]]; s = Select[Range[1, max!], EvenQ[Length[(d = fctBaseDigits[#])]] && Count[d, _?EvenQ] == Length[d]/2 &]; ind = Position[Differences[s], 2] // Flatten; s[[ind]] %Y A351896 Subsequence of A351895. %Y A351896 Cf. A007623, A351893, A351894. %Y A351896 Similar sequence: A337238. %K A351896 nonn,base %O A351896 1,1 %A A351896 _Amiram Eldar_, Feb 24 2022