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A057332 Numbers of (2n+1)-digit palindromic primes that undulate. 1
4, 15, 52, 210, 1007, 5156, 25571, 133293, 727082, 3874464, 21072166 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

'Undulate' means that the alternate digits are consistently greater than or less than the digits adjacent to them (e.g. 906343609). Smoothly undulating palindromic primes (e.g. 323232323) are a subset and included in the count.

REFERENCES

C. A. Pickover, "Wonders of Numbers", Oxford New York 2001, Chapter 52, pp. 123-124, 316-317.

LINKS

Table of n, a(n) for n=0..10.

C. K. Caldwell, Prime Curios! 906343609 and Prime Curios! 1007

C. A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Zentralblatt review

Eric Weisstein's World of Mathematics, Undulating Number.

CROSSREFS

Cf. A046075, A033619, A032758, A039944, A016073, A046076, A046077, A057333.

Sequence in context: A161125 A027295 A208722 * A230623 A162978 A171309

Adjacent sequences:  A057329 A057330 A057331 * A057333 A057334 A057335

KEYWORD

nonn,base,more

AUTHOR

Patrick De Geest, Sep 15 2000.

EXTENSIONS

a(5) from Donovan Johnson, Aug 08 2010

a(6)-a(10) from Lars Blomberg, Nov 19 2013

STATUS

approved

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Last modified September 23 21:16 EDT 2017. Contains 292391 sequences.