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 A321151 #39 Nov 28 2018 09:23:54 %S A321151 409,1021,1069,1201,1609,2089,3061,5209,9601,10069,10369,18049,20089, %T A321151 20809,37021,37201,40009,44089,44809,50329,50929,52009,59029,59209, %U A321151 60889,62401,70921,79201,96001,100069,100609,101449,102001,102769,103069,104161,106129,106801,108769,109321 %N A321151 Primes that yield squares after deletion of their zero digits. %C A321151 Subsequence of A056709. The squares divisible by 2, 3 or 5 cannot be obtained. Most of the squares obtained seem to be squares of prime or semiprime numbers. Among the first 399 squares obtained are 289 squares of prime numbers, 104 squares of semiprimes and 6 other squares; these squares were obtained by testing the prime numbers up to 10^7. Deletion of the zero digits from primes up to 10^8 yields 929 squares of prime numbers, 506 squares of semiprimes and 47 other squares. Do similar results occur when larger primes are considered? %C A321151 From _David A. Corneth_, Nov 26 2018: (Start) %C A321151 Terms can be obtained by listing squares coprime to 30, inserting zeros between digits, and testing the primality of the resulting numbers. %C A321151 Records for omega(s) where s is a square producing a term occur at terms 409, 50929, 10713481, 3601722361, 1531869148081, 807916258118689. (End) %H A321151 David A. Corneth, <a href="/A321151/b321151.txt">Table of n, a(n) for n = 1..17124</a> (terms < 10^10) %H A321151 David A. Corneth, <a href="/A321151/a321151.gp.txt">PARI program</a> %e A321151 409 is prime and 49 = 7^2 is a square. %e A321151 9601 is prime and 961 = 31^2 is a square. %e A321151 20809 is prime and 289 = 17^2 is a square. %e A321151 10069 is prime and 169 = 13^2 is a square. %e A321151 103069 is prime and 1369 = 37^2 is a square. %e A321151 1030069 is prime and 1369 = 37^2 is a square. %t A321151 aQ[n_] := PrimeQ[n] && IntegerQ[Sqrt[FromDigits[Select[IntegerDigits[n], #!=0 &]]]]; Select[Range[100000], aQ] (* _Amiram Eldar_, Nov 25 2018 *) %o A321151 (PARI) isok(p) = isprime(p) && issquare(fromdigits(select(x->x, digits(p)))); \\ _Michel Marcus_, Nov 26 2018 %o A321151 (PARI) \\ See Corneth link \\ _David A. Corneth_, Nov 26 2018 %Y A321151 Cf. A000040, A000290, A052041, A056709, A256186. %K A321151 nonn,base %O A321151 1,1 %A A321151 _Marius A. Burtea_, Nov 23 2018