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A061513
a(0) = 0; a(n) is obtained by incrementing each digit of a(n-1) by 2.
1
0, 2, 4, 6, 8, 10, 32, 54, 76, 98, 1110, 3332, 5554, 7776, 9998, 11111110, 33333332, 55555554, 77777776, 99999998, 1111111111111110, 3333333333333332, 5555555555555554, 7777777777777776, 9999999999999998, 11111111111111111111111111111110, 33333333333333333333333333333332
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.
Every term > 8 is made up of only two different consecutive digits, the smaller of which occurs only as the least significant digit.
Otherwise said, these are one less than the odd repdigits (A010785) of length 2^k, cf. formula. - M. F. Hasler, Jun 24 2016
FORMULA
a(n) = A061512(n)-1 = (10^2^floor(n/5)-1)/9*(n%5*2+1) - 1, where n%5 means the remainder (in {0..4}) of n divided by 5. - M. F. Hasler, Jun 24 2016
EXAMPLE
Following 32; 3+2 = 5 and 2+2 = 4, hence the next term is 54.
MATHEMATICA
NestList[FromDigits[Flatten[IntegerDigits/@(IntegerDigits[#]+2)]]&, 0, 30] (* Harvey P. Dale, Jul 07 2012 *)
PROG
(PARI) A061513(n)=10^2^(n\5)\9*(n%5*2+1)-1 \\ M. F. Hasler, Jun 24 2016
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, May 08 2001
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001
STATUS
approved