cp's OEIS Frontend

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.

A246973 n^2 concatenated with (n+1)^2.

Original entry on oeis.org

1, 14, 49, 916, 1625, 2536, 3649, 4964, 6481, 81100, 100121, 121144, 144169, 169196, 196225, 225256, 256289, 289324, 324361, 361400, 400441, 441484, 484529, 529576, 576625, 625676, 676729, 729784, 784841, 841900, 900961, 9611024, 10241089, 10891156, 11561225, 12251296, 12961369, 13691444
Offset: 0

Views

Author

N. J. A. Sloane, Sep 13 2014

Keywords

Examples

			a(2) = 49 because 2^2 = 4 and 3^2 = 9.
a(3) = 916 because 3^2 = 9 and 4^2 = 16.
a(4) = 1625 because 4^2 = 16 and 5^2 = 25.
		

Crossrefs

For primes see A104242.
Cf. A235497.

Programs

  • Magma
    [1] cat [Seqint(Intseq(n^2+2*n+1) cat Intseq(n^2)): n in [1..50]]; // Vincenzo Librandi, Sep 13 2014
    
  • Maple
    a:= n-> parse(cat(n^2, (n+1)^2)):
    seq(a(n), n=0..40);  # Alois P. Heinz, May 27 2018
  • Mathematica
    Table[FromDigits[Join[IntegerDigits[n^2], IntegerDigits[(n + 1)^2]]], {n, 0, 39}] (* Alonso del Arte, Sep 13 2014 *)
  • PARI
    a(n) = eval(Str(n^2,(n+1)^2)) \\ Michel Marcus, Sep 13 2014 and M. F. Hasler, May 27 2018
    
  • 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