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A115657 Both n and the reverse of n are pentagonal numbers (A000326). 0
1, 5, 22, 210, 287, 782, 1001, 2882, 7740, 15251, 77180, 565187, 720027, 781565, 7081807, 7451547, 26811862, 54177145, 206489067, 246214610, 760984602, 1050660501, 1085885801, 1528888251, 2642326276, 2911771192, 6726232462 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..27.

EXAMPLE

565187=P(614) and 781565=P(722), where P(k)=k(3k-1)/2 is the k-th pentagonal number.

CROSSREFS

Cf. A000326, A061455, A061457.

Sequence in context: A048252 A208804 A066866 * A066865 A183902 A005632

Adjacent sequences:  A115654 A115655 A115656 * A115658 A115659 A115660

KEYWORD

base,nonn

AUTHOR

Giovanni Resta, Jan 28 2006

STATUS

approved

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Last modified June 1 04:57 EDT 2020. Contains 334758 sequences. (Running on oeis4.)