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A194041 Lucky numbers which are also unhappy numbers. 1
3, 9, 15, 21, 25, 33, 37, 43, 51, 63, 67, 69, 73, 75, 87, 93, 99, 105, 111, 115, 127, 135, 141, 151, 159, 163, 169, 171, 189, 195, 201, 205, 211, 223, 231, 235, 237, 241, 259, 261, 267, 273, 283, 285, 289, 297, 303, 307, 321, 327, 339, 349, 357, 361, 385, 393 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

An unhappy number is a number that is not happy (A007770) i.e., a number n such that iterating this sum-of-squared-digits map starting with n never reaches the number 1. Many asymptotic properties of the prime numbers are shared by the lucky numbers.

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..1000

Eric W. Weisstein, Unhappy Number

Eric W. Weisstein, Lucky Number

FORMULA

A000959 INTERSECTION A031177. {k such that k is in A000959 and k is not in A007770}.

CROSSREFS

Cf. A000959, A007770, A031177.

Sequence in context: A307202 A162488 A324298 * A029506 A299790 A030594

Adjacent sequences:  A194038 A194039 A194040 * A194042 A194043 A194044

KEYWORD

nonn,easy

AUTHOR

Jonathan Vos Post, Aug 12 2011

STATUS

approved

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Last modified October 14 00:32 EDT 2019. Contains 327991 sequences. (Running on oeis4.)