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 A061512 a(0) = 1; a(n) is obtained by incrementing each digit of a(n-1) by 2. 5
 1, 3, 5, 7, 9, 11, 33, 55, 77, 99, 1111, 3333, 5555, 7777, 9999, 11111111, 33333333, 55555555, 77777777, 99999999, 1111111111111111, 3333333333333333, 5555555555555555, 7777777777777777, 9999999999999999, 11111111111111111111111111111111, 33333333333333333333333333333333 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc. Also: odd repdigits (A010785) of length 2^k, cf. formula. - M. F. Hasler, Jun 24 2016 LINKS FORMULA a(n) = (10^2^floor(n/5)-1)/9*(n%5*2+1), where n%5 means the remainder (in {0..4}) of n divided by 5. - M. F. Hasler, Jun 24 2016 EXAMPLE Following 33: 3+2 = 5 and 3+2 = 5, hence the next term is 55. MATHEMATICA NestList[FromDigits[Flatten[IntegerDigits/@(IntegerDigits[#]+2)]]&, 1, 30] (* Harvey P. Dale, Apr 13 2012 *) PROG (PARI) A061512(n)=10^2^(n\5)\9*(n%5*2+1) \\ M. F. Hasler, Jun 24 2016 (PARI) nxt(n) = my(d=digits(n)); if(d[1]<9, n+2*(10^#d - 1)/9, (10^(2*#d) - 1)/9) inv(n) = {my(d=digits(n)); 5*logint(#d, 2) + (d[1]+1)\2} \\ David A. Corneth, Jun 24 2016 CROSSREFS Cf. A061511 - A061522, A061746 - A061750; A061581 - A061587. Cf. also A010785. Sequence in context: A029950 A061507 A046497 * A083964 A131628 A079091 Adjacent sequences:  A061509 A061510 A061511 * A061513 A061514 A061515 KEYWORD base,nonn AUTHOR Amarnath Murthy, May 08 2001 EXTENSIONS More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001 STATUS approved

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Last modified August 7 17:44 EDT 2020. Contains 336278 sequences. (Running on oeis4.)