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 A359510 #13 Jan 31 2023 08:25:29 %S A359510 23,26,29,30,34,35,37,38,43,47,53,57,59,62,65,67,70,73,74,79,82,83,85, %T A359510 86,87,89,92,94,95,97,103,106,107,109,123,127,130,134,137,139,140,142, %U A359510 145,146,148,149,152,157,158,163,167,170,173,174,178,179,182,183,185,190,193,194,197 %N A359510 Numbers that can't be written as a palindromic product, i.e., such that the concatenation of all digits of the factors yields a palindrome. %C A359510 Any number of factors 1 is allowed anywhere in the product. %C A359510 The sequence contains all primes which are not palindromic when stripped of digits '1' on either side (for example 23, 29, 37, but not 13, 17, 19, 31 which can be written as 13*1, 17*1, 19*1, 1*31, etc., where the concatenation of all digits, "131", "171", ... is palindromic). %H A359510 Eric Angelini, <a href="https://mailman.xmission.com/hyperkitty/list/math-fun@mailman.xmission.com/thread/M65EFRTIUYJKT72QAYOOMVD7BVFSYP7Z/">2023 = 7*17*17, a palindromic product</a>, math-fun list (restricted to subscribers), Jan. 1, 2023. %e A359510 Any palindrome is trivially a palindromic product and therefore not in the sequence. Also not in the sequence are 10 = 10*1, 12 = 12*1, ..., 20 = 2*5*2, 21 = 1*21. Therefore the first term is a(1) = 23. %Y A359510 Cf. A002113 (palindromes in base 10), A029742 (non-palindromes), A334321 (non-palindromic primes), A004176 (omit digits 1). %K A359510 nonn,base %O A359510 1,1 %A A359510 _M. F. Hasler_ and _Eric Angelini_, Jan 03 2023