

A057333


Numbers of ndigit primes that undulate.


1



4, 21, 74, 347, 1743, 8385, 44355, 229952, 1235489, 6629026, 37152645, 202017712
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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. 123124, 316317.


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



