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.

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A240562 Integers whose squares are in A000073 (tribonacci numbers).

Original entry on oeis.org

0, 1, 2, 9, 56, 103
Offset: 1

Views

Author

J. Lowell, Apr 16 2014

Keywords

Comments

a(6) > 10^7. - Tom Edgar, Apr 26 2014
Is this sequence finite?
No more terms < 10^19300. I conjecture that the sequence is finite. - Manfred Scheucher, Aug 17 2015

Examples

			9^2 = 81 is in the tribonacci sequence, so 9 is a term.
		

Crossrefs

Cf. A000073 (tribonacci numbers), A128911 (the corresponding squares).

Programs

  • Mathematica
    Select[Sqrt[#]&/@LinearRecurrence[{1,1,1},{0,0,1},200],IntegerQ]// Union (* Harvey P. Dale, Aug 16 2021 *)
  • Sage
    def tribs():
        a,b,c = 0,0,1
        while True:
            yield a
            a,b,c = b,c,a+b+c
    for n in tribs():
        m = sqrt(n)
        if m.is_integer():
            print(m) # Manfred Scheucher, Aug 17 2015

Extensions

Zero prepended by Harvey P. Dale, Aug 16 2021
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