

A071440


Start with 1; add the digits of the previous term and the squares of the digits of the previous term.


2



1, 2, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48, 92, 96, 132, 20, 6, 42, 26, 48
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OFFSET

0,2


COMMENTS

The sequence becomes periodic after ten steps: a(10) = a(2). Period length is 8, length of the preperiodic part is 2.  Other starting values except 9, 90, 900, ... result in sequences which exhibit essentially the same behavior.


LINKS

Table of n, a(n) for n=0..69.


EXAMPLE

42 > 4 + 2 + 4^2 + 2^2 = 26, 26 > 2 + 6 + 2^2 + 6^2 = 48, ...


PROG

(PARI) {m=70; a=1; for(j=1, m, print1(a, ", "); n=a; a=0; while(n>0, d=divrem(n, 10); n=d[1]; a=a+(1+d[2])*d[2]))}


CROSSREFS

Sequence in context: A326268 A096138 A004153 * A280043 A309813 A033936
Adjacent sequences: A071437 A071438 A071439 * A071441 A071442 A071443


KEYWORD

nonn,base,easy


AUTHOR

N. J. A. Sloane, Oct 23 2002


EXTENSIONS

Edited and extended by Klaus Brockhaus, Oct 24 2002


STATUS

approved



