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A027568
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Numbers that are both triangular and tetrahedral.
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4
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OFFSET
| 1,3
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REFERENCES
| Avanesov, E. T.; Solution of a problem on figurate numbers. (Russian) Acta Arith. 12 1966/1967 409-420.
J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 10, p. 3 ; Entry 119, p. 41, Ellipses, Paris 2008.
L. J. Mordell, Diophantine Equations, Ac. Press, p. 258.
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LINKS
| P. De Geest, Palindromic Tetrahedrals
Eric Weisstein's World of Mathematics, More information
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MAPLE
| {seq(binomial(i, 3), i=0..100000) } intersect {seq(binomial(k, 2), k= 0..100000)}; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 26 2008
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MATHEMATICA
| f3[n_]:=n*(n+1)*(n+2)/6; TriangularNumberQ[n_]:=Floor[Sqrt[2*n]]*(Floor[Sqrt[2*n]]+1)/2==n; Select[f3[Range[5! ]], TriangularNumberQ[ # ]&] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 16 2010]
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CROSSREFS
| Intersection of A000217 and A000292. Cf. A102349, A102461, A102772.
Sequence in context: A182605 A024127 A005949 * A034255 A051582 A122420
Adjacent sequences: A027565 A027566 A027567 * A027569 A027570 A027571
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KEYWORD
| nonn,fini,full
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com)
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