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 A248506 Lucas numbers that are also triangular numbers. 2
 1, 3, 5778 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Intersection of A000032 and A000217. All terms are shown, see Theorem 1.1 in the Tengely reference. - Joerg Arndt, Dec 06 2014 LINKS Table of n, a(n) for n=1..3. Luo Ming, On Triangular Fibonacci Numbers, The Fibonacci Quarterly, 27.2 (1989), pp. 98-108. Luo Ming, On Triangular Lucas Numbers, Applications of Fibonacci Numbers, 1991, pp 231-240. Szabolcs Tengely, Finding g-gonal numbers in recurrence sequences, Fibonacci Quarterly, vol.46/47, no.3, pp.235-240, (2009). EXAMPLE Lucas(18) = 5778 = 107*108/2. MATHEMATICA Select[LucasL[Range[20]], OddQ[Sqrt[1+8#]]&] (* Harvey P. Dale, Oct 18 2015 *) PROG (PARI) L0=2; L1=1 { for(k=1, 10^9, if ( ispolygonal(L0, 3), print1(L0, ", ") ); [L0, L1] = [L1, L1 + L0]; ); } \\ Joerg Arndt, Dec 06 2014 CROSSREFS Cf. A000032, A000217, A039595. Sequence in context: A171362 A249511 A362099 * A368622 A034317 A185671 Adjacent sequences: A248503 A248504 A248505 * A248507 A248508 A248509 KEYWORD nonn,fini,full,bref AUTHOR Vincenzo Librandi, Dec 06 2014 STATUS approved

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Last modified February 22 06:21 EST 2024. Contains 370240 sequences. (Running on oeis4.)