A292850 Lucas numbers that are also generalized heptagonal numbers.

1, 4, 7, 18

Offset

1,2

Comments

Intersection of A000032 and A085787.

Except 4, these are also ordinary heptagonal numbers.

All terms are shown, as confirmed by Srinivasa Rao (2002).

All (generalized) g-gonal numbers in Lucas sequences up to g=20 have been determined, see Tengely (2009).

Links

Table of n, a(n) for n=1..4.

B. Srinivasa Rao, Heptagonal Numbers in the Lucas Sequence and Diophantine Equations x^2(5x-3)^2 = 20y^2+-16, The Fibonacci Quarterly, Vol. 40, No. 4 (2002), 319-322.

Szabolcs Tengely, Finding g-gonal numbers in recurrence sequences, Fibonacci Quarterly, vol.46/47, no.3, pp.235-240, (2009).

Crossrefs

Cf. A000032, A085787.

Cf. A248506 (triangular Lucas Numbers).

Sequence in context: A319782 A057450 A077274 * A080650 A276187 A357041

Adjacent sequences: A292847 A292848 A292849 * A292851 A292852 A292853

Keyword

nonn,easy,full,fini

Author

Tomohiro Yamada, Sep 25 2017

Status

approved