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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
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
Sequence in context: A171362 A249511 A362099 * A368622 A034317 A185671
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.)