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A224753
a(2)=2; thereafter a(n) = smallest number m such that a(n-1)+m = (a(n-1) followed by the leading digit of m).
0
2, 19, 172, 1549, 13942, 125479, 1129312, 10163809, 91474290, 823268618, 7409417569, 66684758127, 600162823149, 5401465408346, 48613188675118, 437518698076066, 3937668282684597, 35439014544161376, 318951130897452387, 2870560178077071485, 25835041602693643367, 232515374424242790305, 2092638369818185112747
OFFSET
1,1
COMMENTS
The sequence is infinite: a(n) always exists.
For computer programs and examples see A224752.
Appears to be (1/4) * #{ k < 10^n | 2k has no digit 0 }, at least up to n = 8. Has anyone a simple explanation for this? - M. F. Hasler, Oct 10 2019
REFERENCES
Eric Angelini, Postings to the Sequence Fans Mailing List, Apr 13 2013
LINKS
Eric Angelini, Magic Sums
E. Angelini, Magic Sums [Cached copy, with permission]
PROG
(PARI) A224753_vec(N=30)=vector(N, n, N=if(n>1, A224752_nxt(N), 2)) \\ M. F. Hasler, Oct 10 2019
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Apr 21 2013
STATUS
approved