|
%I #25 Sep 08 2022 08:46:09
%S 1,14,49,916,1625,2536,3649,4964,6481,81100,100121,121144,144169,
%T 169196,196225,225256,256289,289324,324361,361400,400441,441484,
%U 484529,529576,576625,625676,676729,729784,784841,841900,900961,9611024,10241089,10891156,11561225,12251296,12961369,13691444
%N n^2 concatenated with (n+1)^2.
%H Vincenzo Librandi, <a href="/A246973/b246973.txt">Table of n, a(n) for n = 0..1000</a>
%e a(2) = 49 because 2^2 = 4 and 3^2 = 9.
%e a(3) = 916 because 3^2 = 9 and 4^2 = 16.
%e a(4) = 1625 because 4^2 = 16 and 5^2 = 25.
%p a:= n-> parse(cat(n^2, (n+1)^2)):
%p seq(a(n), n=0..40); # _Alois P. Heinz_, May 27 2018
%t Table[FromDigits[Join[IntegerDigits[n^2], IntegerDigits[(n + 1)^2]]], {n, 0, 39}] (* _Alonso del Arte_, Sep 13 2014 *)
%o (Magma) [1] cat [Seqint(Intseq(n^2+2*n+1) cat Intseq(n^2)): n in [1..50]]; // _Vincenzo Librandi_, Sep 13 2014
%o (PARI) a(n) = eval(Str(n^2,(n+1)^2)) \\ _Michel Marcus_, Sep 13 2014 and _M. F. Hasler_, May 27 2018
%o (PARI) A246973(n)=n^2*10^logint(10*(n+1)^2,10)+(n+1)^2 \\ Over 4 x faster than using eval(Str(...)). - _M. F. Hasler_, May 27 2018
%Y For primes see A104242.
%Y Cf. A235497.
%K nonn,base,easy
%O 0,2
%A _N. J. A. Sloane_, Sep 13 2014
|
