This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A098670 Start with a(1) = 5. Construct slowest growing sequence such that the statement "the a(n)-th digit is a 2" is true for all n. 4
 5, 6, 7, 8, 22, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The sequence goes 5, 6, 7, 8, 22, 220, 221, ..., 290, 2222, 22222, 222222, ... for 275 more digits, then for most of the rest of the sequence, a(n+1)=a(n)+1. Starting with a(1)=3 yields 3, 4, 22, 23, ..., 30, 32, 222, 2222, 2223,... for at least 2000 more digits. (The 222nd digit happens to be the initial digit of a(63)=2271.) Starting with a(1)=4 yields 4, 5, 6, 22, 23, ..., 30, 222, 2222, 2223, ... See A210416 for a variant without requirement of growth. - M. F. Hasler, Oct 08 2013 LINKS EXAMPLE The 5th digit of the sequence is a "2", the 6th digit also, then the 7th, the 8th, the 22nd etc. PROG (PARI) { a=5; P=Set(); L=0; while(1, print1(a, ", "); P=setunion(P, Set([a])); L+=#Str(a); until(g, g=1; a++; s=Vec(Str(a)); for(i=1, #s, if(setsearch(P, L+i)&&s[i]!="2", g=0; break)); ); ) } \\ Max Alekseyev CROSSREFS Cf. A114134, A098645, A210414-A210423. Sequence in context: A219331 A229862 A302599 * A320021 A081407 A268857 Adjacent sequences:  A098667 A098668 A098669 * A098671 A098672 A098673 KEYWORD base,easy,nonn AUTHOR Eric Angelini, Oct 27 2004 EXTENSIONS Edited and extended by Max Alekseyev, Feb 06 2010 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 September 19 11:06 EDT 2019. Contains 327192 sequences. (Running on oeis4.)