login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A193570 Unhappy numbers which enter the cycle (4, 16, 37, 58, 89, 145, 42, 20) at 145. 0
77, 98, 145, 149, 194, 238, 283, 289, 298, 328, 358, 382, 385, 419, 456, 465, 491, 538, 546, 564, 583, 645, 654, 678, 687, 707, 768, 770, 786, 789, 798, 809, 823, 829, 832, 835, 853, 867, 876, 879, 890, 892, 897, 908, 914, 928, 941, 978, 980, 982, 987 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Unhappy Number.
EXAMPLE
25889 is such a number of height 4 because it enters the cycle at 145 in 4 steps: 25889 -> 238 -> 77 -> 98 -> 145 -> 42 -> 20 -> 4 -> 16 -> 37 -> 58 -> 89 -> 145 -> ...
MAPLE
S:=proc(n) local Q, k, N, z; Q:=[n]; for k from 1 do N:=convert(Q[k], base, 10); z:=sum(N['i']^2, 'i'=1..nops(N)); if not member(z, Q) then Q:=[op(Q), z]; else Q:=[op(Q), z]; break; fi; od; return Q; end:
a:=[]: for i from 1 while nops(a)<30 do Q:=S(i); A:=Q[nops(Q)]; if A=145 then a:=[op(a), i] fi; od: print(op(a));
CROSSREFS
Sequence in context: A064902 A247682 A127335 * A154534 A235867 A274967
KEYWORD
nonn,base
AUTHOR
Martin Renner, Jul 31 2011
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 19 16:52 EDT 2024. Contains 371794 sequences. (Running on oeis4.)