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A057333 Numbers of n-digit primes that undulate. 1
4, 21, 74, 347, 1743, 8385, 44355, 229952, 1235489, 6629026, 37152645, 202017712 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

'Undulate' means that the alternate digits are consistently greater than or less than the digits adjacent to them (e.g. 70769). Smoothly undulating palindromic primes (e.g. 95959) 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=1..12.

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, A057332.

Sequence in context: A095668 A078800 A184706 * A034960 A240372 A157493

Adjacent sequences:  A057330 A057331 A057332 * A057334 A057335 A057336

KEYWORD

nonn,base,more

AUTHOR

Patrick De Geest, Sep 15 2000.

EXTENSIONS

Offset corrected and a(10)-a(11) from Donovan Johnson, Aug 08 2010

a(12) from Giovanni Resta, Feb 24 2013

STATUS

approved

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