A248506 -id:A248506 - cp's OEIS frontend

A292850 Lucas numbers that are also generalized heptagonal numbers.

1, 4, 7, 18

Offset: 1

Tomohiro Yamada, Sep 25 2017

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).

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).

Cf. A000032, A085787.

Cf. A248506 (triangular Lucas Numbers).

A293023 Generalized pentagonal numbers that are also Pell numbers.

Original entry on oeis.org

0, 1, 2, 5, 12, 70

Offset: 0

Tomohiro Yamada, Sep 29 2017

Intersection of A000129 and A001318.
Except for 0 and 2, these are also ordinary pentagonal numbers.
All terms are shown, as confirmed by Siva Rama Prasad and Srinivasa Rao (2002).
All (generalized) g-gonal numbers in the Pell sequence up to g=20 have been determined, see Tengely (2009).

V. Sima Rama Prasad and B. Srinivasa Rao, Pentagonal Numbers in the Pell Sequence and Diophantine Equations 2x^2=y^2(3y-1)^2+-2, The Fibonacci Quarterly, Vol. 40, No. 3 (2002), 233-241.
Szabolcs Tengely, Finding g-gonal numbers in recurrence sequences, Fibonacci Quarterly, vol.46/47, No. 3 (2009), 235-240.

Cf. A000129, A001318.

Cf. A039595, A248506, A292851.

cp's OEIS Frontend

A292850 Lucas numbers that are also generalized heptagonal numbers.

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A293023 Generalized pentagonal numbers that are also Pell numbers.

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