The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A122065 Take sum of squares of digits of previous term; start with 74169. 14
74169, 183, 74, 65, 61, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
From a quiz, cf. Russel & Carter reference.
REFERENCES
K. Russell and P. Carter, Number Puzzles, W. Foulsham and Co. Ltd. (1993).
LINKS
FORMULA
a(n) = A000218(n) for n >= 4, a(n) = A000216(n-2) for n >= 6. - M. F. Hasler, Apr 27 2018
MATHEMATICA
NestList[Total[IntegerDigits[#]^2]&, 74169, 80] (* Vincenzo Librandi, Jan 29 2013 *)
PROG
(Magma) [74169, 183, 74, 65, 61] cat &cat[[37, 58, 89, 145, 42, 20, 4, 16]: n in [0..17]]; // Vincenzo Librandi, Jan 29 2013
(PARI) A122065_vec=vector(50, n, t=if(n>1, norml2(digits(t)), 74169));
A122065(n)=A122065_vec[n%8+(n>7)*8] \\ M. F. Hasler, Apr 27 2018
CROSSREFS
Cf. A000216 (main entry for related sequences), A003132 (the iterated "sum digits squared" map).
Sequence in context: A256731 A186835 A239587 * A079543 A033450 A033448
KEYWORD
nonn,base,easy
AUTHOR
Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 14 2006
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 June 17 15:57 EDT 2024. Contains 373463 sequences. (Running on oeis4.)