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

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A228878 Happy squares: squares whose trajectory under iteration of sum of squares of digits map includes 1. 1
 1, 49, 100, 784, 1444, 1521, 3364, 4096, 4225, 4356, 4900, 7225, 7744, 8281, 9604, 10000, 11025, 12321, 12996, 14641, 15625, 17424, 17956, 22201, 24025, 27225, 27556, 27889, 28561, 29584, 34596, 37636, 42025, 45369, 54289, 55696, 56644, 59049, 59536, 63504 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This was a puzzle mentioned on The Aperiodical website. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 MATHEMATICA f[n_] := Total[IntegerDigits[n]^2]; Select[Range[400]^2, NestWhile[f, #, UnsameQ, All] == 1 &] PROG (PARI) ssd(n)=n=digits(n); sum(i=1, #n, n[i]^2) select(n->while(n>6, n=ssd(n)); n==1, vector(1000, i, i^2)) \\ Charles R Greathouse IV, Dec 17 2013 CROSSREFS Intersection of A000290 and A007770. Sequence in context: A354342 A230653 A019547 * A067673 A250653 A045253 Adjacent sequences: A228875 A228876 A228877 * A228879 A228880 A228881 KEYWORD nonn,base AUTHOR T. D. Noe, Oct 07 2013 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.

Last modified December 4 23:46 EST 2022. Contains 358572 sequences. (Running on oeis4.)