The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A002069 Palindromic pentagonal numbers. (Formerly M3924 N1612) 5
 0, 1, 5, 22, 1001, 2882, 15251, 720027, 7081807, 7451547, 26811862, 54177145, 1050660501, 1085885801, 1528888251, 2911771192, 2376574756732, 5792526252975, 5875432345785, 10810300301801, 264571020175462, 5292834004382925, 10808388588380801, 15017579397571051 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Robert Price, Table of n, a(n) for n = 1..30 P. De Geest, More about Palindromic Pentagonals A. Gloden and R. A. Johnson, Problem E427, Amer. Math. Monthly, 48 (1941), 211-212. MATHEMATICA Select[PolygonalNumber[5, Range[0, 6*10^7]], PalindromeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 15 2018 *) CROSSREFS Cf. A028386, A000326. Sequence in context: A299215 A300031 A271678 * A298233 A215742 A357948 Adjacent sequences: A002066 A002067 A002068 * A002070 A002071 A002072 KEYWORD nonn,base AUTHOR N. J. A. Sloane STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 4 08:18 EDT 2023. Contains 365873 sequences. (Running on oeis4.)