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 A382765 #32 Apr 17 2025 09:51:15 %S A382765 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89, %T A382765 103,107,113,139,149,151,163,167,173,181,197,211,223,227,229,257,263, %U A382765 311,353,359,367,373,379,389,479,569,571,643,691,727,733,751,877,1019,1091,1699,2239,2357,2749,2753 %N A382765 Primes that can be expressed using exactly one of each of the prime digits 2, 3, 5, 7, using concatenation and the arithmetic operations +,-,*,/,^. %C A382765 Concatenation is only allowed for individual digits, not expressions, so 37 - 2^5 = 5 is allowed but (7 + 2 - 5)3 = 43 is not allowed. %H A382765 Robert Israel, <a href="/A382765/b382765.txt">Table of n, a(n) for n = 1..83</a> (full sequence) %H A382765 Robert Israel, <a href="/A382765/a382765_2.txt">Maple code</a> %H A382765 Robert Israel, <a href="/A382765/a382765_3.txt">An expression for each term</a> %e A382765 a(1) = 2 = (3 - 2) * (7 - 5). %e A382765 a(2) = 3 = 2 + 3 + 5 - 7. %e A382765 a(3) = 5 = 37 - 2^5. %e A382765 a(4) = 7 = 2 + 3 - 5 + 7. %e A382765 a(83) = 4747561509941 = 7 ^ (3 * 5) - 2. %p A382765 See link. %Y A382765 Cf. A382901. %K A382765 nonn,base,fini,full %O A382765 1,1 %A A382765 _Zak Seidov_ and _Robert Israel_, Apr 10 2025