A193996 - OEIS

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 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A193996

Numbers that require exactly 8 iterations to determine that they are happy or not (A007770 and A031177).

4, 16, 20, 37, 42, 58, 89, 145, 78999, 79899, 79989, 79998, 87999, 89799, 89979, 89997, 97899, 97989, 97998, 98799, 98979, 98997, 99789, 99798, 99879, 99897, 99978, 99987, 378999, 379899, 379989, 379998, 387999, 389799, 389979, 389997, 389999, 397899, 397989

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

This sequence begins with the last 8 numbers of A039943. The number 78999 is the first happy number here.

LINKS

Table of n, a(n) for n=1..39.

MATHEMATICA

f[n_] := Total[IntegerDigits[n]^2]; Select[Range[400000], Length[NestWhileList[f, #, UnsameQ, All]] - 1 == 8 &]

CROSSREFS

Sequence in context: A326781 A326788 A039943 * A232400 A345763 A354712

Adjacent sequences: A193993 A193994 A193995 * A193997 A193998 A193999

KEYWORD

nonn,base

AUTHOR

T. D. Noe, Aug 23 2011

STATUS

approved