This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A256639 a(n) is the base-(-10) representation of a(n-1) read in base 10, starting from -1. 0
 -1, 19, 199, 219, 399, 419, 599, 619, 799, 819, 999, 19019, 21199, 39219, 41399, 59419, 61599, 79619, 81799, 99819, 1901999, 2118019, 3922199, 4138219, 5942399, 6158419, 7962599, 8178619, 9982799, 190198819, 211802999, 392217019, 413823199, 594237219, 615843399, 796257419, 817863599, 998277619, 19019883799 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Decimal -1 in negadecimal is 19, decimal 19 in negadecimal is 199, decimal 199 in negadecimal is 219, .... LINKS MATHEMATICA negaDecimal[n_] := Mod[NestWhileList[Function[k, (Mod[k, 10]-k)/10], n, # != 0&], 10] // Reverse // Rest // FromDigits; a[1] = -1; a[n_] := a[n] = negaDecimal[a[n-1]]; Array[a, 40] (* Jean-François Alcover, Nov 23 2016 *) PROG (HP 49G calculator) Given a(n) the program produces a(n+1). ::   CK1&Dispatch   # FF   ::     Z10_     ZINT -10     FPTR2 ^2LAMBIND     NULL\$SWAP     BEGIN     1GETLAM     FPTR2 ^IDIV2     FPTR2 ^DupQIsZero?     ?SKIP     ::       2GETLAM       FPTR2 ^RADDext       SWAP       Z1_       FPTR2 ^RADDext       SWAP     ;     FPTR2 ^Z>S     ROT     &\$SWAP     FPTR2 ^DupQIsZero?     UNTIL     ABND     DROP     FPTR2 ^S>Z   ; ; CROSSREFS Cf. A039723. Sequence in context: A210339 A097445 A238697 * A058370 A230012 A164890 Adjacent sequences:  A256636 A256637 A256638 * A256640 A256641 A256642 KEYWORD sign,base AUTHOR Gerald Hillier, Apr 23 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 October 20 12:47 EDT 2019. Contains 328257 sequences. (Running on oeis4.)