The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A250202 The "sum of squares of digits" problem in base 12, start with 6 (written in base 10). 1
 6, 36, 9, 81, 117, 162, 38, 13, 2, 4, 16, 17, 26, 8, 64, 41, 34, 104, 128, 164, 66, 61, 26, 8, 64, 41, 34, 104, 128, 164, 66, 61, 26, 8, 64, 41, 34, 104, 128, 164, 66, 61, 26, 8, 64, 41, 34, 104, 128, 164, 66, 61, 26, 8, 64, 41, 34, 104, 128, 164, 66, 61, 26, 8, 64, 41 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Periodic with period 10. In base 12, there are 3 fixed points and 4 cycles (only 1 fixed point and 1 cycle in base 10, see A161772): 1 -> 1 (length 1); 5 -> 21 -> 5 (length 2); 8 -> 54 -> 35 -> 2a -> 88 -> a8 -> 118 -> 56 -> 51 -> 22 -> 8 (length 10); 18 -> 55 -> 42 -> 18 (length 3); 25 -> 25 (length 1); 68 -> 84 -> 68 (length 2); a5 -> a5 (length 1); Notice 25 (decimal 29) and a5 (decimal 125) are Armstrong numbers in base 12 (A161949), there are no 2-digit Armstrong numbers in base 10. In base 12, there are only few happy numbers (no such between 10 (decimal 12) and 100 (decimal 144)), but in base 10, there are 20 happy numbers less than or equal to 100 (see A007770). LINKS Eric Chen, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 1). MATHEMATICA NestList[Total[IntegerDigits[#, 12]^2]&, 6, 144] Join[{6, 36, 9, 81, 117, 162, 38, 13, 2, 4, 16, 17}, LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {26, 8, 64, 41, 34, 104, 128, 164, 66, 61}, 54]] (* Ray Chandler, Aug 26 2015 *) PadRight[{6, 36, 9, 81, 117, 162, 38, 13, 2, 4, 16, 17}, 80, {66, 61, 26, 8, 64, 41, 34, 104, 128, 164}] (* Harvey P. Dale, Aug 06 2017 *) PROG (PARI) a(n) = [6, 36, 9, 81, 117, 162, 38, 13, 2, 4, 16, 17, 26, 8, 64, 41, 34, 104, 128, 164, 66, 61][n%10+10*(n>=10)+10*(n%10<3 & n>=20)] CROSSREFS Cf. A000216, A000218, A080709, A000221, A008460, A008461, A008462, A008463, A161772. Sequence in context: A059059 A304255 A050112 * A036125 A001311 A137868 Adjacent sequences:  A250199 A250200 A250201 * A250203 A250204 A250205 KEYWORD nonn,easy,base AUTHOR Eric Chen, Mar 13 2015 STATUS approved

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

Last modified January 20 14:47 EST 2021. Contains 340302 sequences. (Running on oeis4.)