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A248050 Lexicographically earliest increasing sequence such that a(n) equals the sum of digits of the terms up to and including a(n). 1
0, 9, 18, 27, 36, 45, 54, 63, 72, 81, 99, 108, 117, 126, 135, 144, 153, 162, 171, 180, 198, 207, 216, 225, 234, 243, 252, 261, 279, 297, 306, 315, 324, 333, 342, 351, 360, 378, 396, 405, 414, 423, 432, 441, 459, 477, 495, 504, 513, 522, 531, 540, 558, 576, 594, 603, 612, 621, 639, 657, 675, 693, 702, 711, 720, 738, 756, 774, 792 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
The offset could equally well be chosen to be 1, but taking it equal to zero allows us to consider {a(n); n=0,1,2...} and {a(n); n=1,2...} together, both of which satisfy the definition.
All terms are divisible by 9, but there is no limit on the size of the gaps. The first gap of 18 occurs after a(9)=81 followed by a(10)=99, the first gap of 27 after a(79)=972 followed by a(80)=999.
There seems also to be no limit on the "look-ahead" required to avoid getting stuck by a bad choice.
LINKS
E. Angelini, Cumulative sum of the digits used so far, SeqFan mailing list, Oct 30 2014
PROG
(PARI) a(n, a=0, L=19)={local(ok(n, L)=!L||for(k=1, #Str(n), sumdigits(n+=9)/9==k&&ok(n, L-1)&&return(n))); for(i=1, n, print1(s=a", "); until(s+sumdigits(a+=9)==a&&ok(a, L), )); a}
CROSSREFS
Sequence in context: A052223 A085132 A111708 * A044052 A131418 A249605
KEYWORD
nonn,base
AUTHOR
Eric Angelini and M. F. Hasler, Oct 30 2014
STATUS
approved

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Last modified September 22 07:44 EDT 2023. Contains 365519 sequences. (Running on oeis4.)