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A293023
Generalized pentagonal numbers that are also Pell numbers.
0
0, 1, 2, 5, 12, 70
OFFSET
0,3
COMMENTS
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).
LINKS
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.
CROSSREFS
KEYWORD
nonn,fini,easy,full
AUTHOR
Tomohiro Yamada, Sep 29 2017
STATUS
approved