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 A271422 #46 Nov 17 2024 16:11:32
%S A271422 24,39,525,749,11121,13169,17289,19361,23529,29841,31961,371369,
%T A271422 411681,431849,472209,532809,593481,613721,674489,715041,735329,
%U A271422 796241,836889,897921,979409,10110201,10310609,10711449,10911881,11312769,12716129,13117161,13718769
%N A271422 Concatenation of prime(n) and its square.
%C A271422 All concatenations are divisible by the n-th prime.
%C A271422 a(n)/prime(n) gives a number of the form concatenate[(10^k)_prime(n)] for some k.
%C A271422 Subsequence of A053061.
%C A271422 Except for 24 and 525, a(n) have final decimal digit 1 or 9.
%F A271422 a(n) = Concatenate [prime(n)_A001248(n)].
%F A271422 a(n) = p*(p+10^A055642(p^2)) with p = prime(n). - _Peter Luschny_, Jul 17 2016
%e A271422 For n=4, prime(4) = 7 (the fourth prime number) and 7^2 = 49. These are concatenated to get a(4) = 749. - _Michael B. Porter_, Jul 16 2016
%p A271422 seq(n*(n+10^(1+ilog10(n^2))), n=select(k->isprime(k),[$1..137])); # _Peter Luschny_, Jul 16 2016
%t A271422 Table[FromDigits@ Flatten@ Map[IntegerDigits, {#, #^2}] &@ Prime@ n, {n, 33}] (* _Michael De Vlieger_, Jul 13 2016 *)
%o A271422 (PARI) a(n) = eval(Str(prime(n), prime(n)^2)) \\ _Felix Fröhlich_, Jul 14 2016
%Y A271422 Cf. A001248 (primes squared), A030078 (primes cubed), A053061, A038800 (number of primes between 10n and 10n+9).
%K A271422 nonn,easy,base
%O A271422 1,1
%A A271422 _Giovanni Teofilatto_, Jul 13 2016