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 A372336 #8 Apr 28 2024 09:35:11 %S A372336 6,51,91,106,219,323,406,435,437,518,529,609,614,626,629,634,658,703, %T A372336 705,818,826,838,878,906,938,978,2051,2093,2173,3053,3241,4151,4171, %U A372336 4281,5041,5063,5141,5183,5241,6251,6591,7021,7081,7251,8051,8121,8491,8571,8781,9121,9231,9291,9583 %N A372336 For a positive number k, let L(k) denote the list consisting of k followed by the prime factors of k, with repetition, in nondecreasing order; sequence gives composite k such that the digits of L(k) alternate being smaller than and then larger than the previous digit. %C A372336 No term can end in 0 or 2; a number ending in 2 would mean the first prime factor is 2, which would disqualify the number, while a number ending in 0 would mean the first 3 distinct prime factors would have to be 2, 3, 5 or 2, 5, either of which would also disqualify the number. %H A372336 Scott R. Shannon, <a href="/A372336/b372336.txt">Table of n, a(n) for n = 1..10000</a> %e A372336 106 is a term as 106 = 2 * 53 which when concatenated give "106253", the digits of which alternate from being smaller than and then larger than the previous digit. %Y A372336 Cf. A372335, A372280, A372308, A372034, A372029, A056704. %K A372336 nonn,base %O A372336 1,1 %A A372336 _Scott R. Shannon_, Apr 28 2024