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 A153848 Repeat 21. 1
 21, 2121, 212121, 21212121, 2121212121, 212121212121, 21212121212121, 2121212121212121, 212121212121212121, 21212121212121212121, 2121212121212121212121, 212121212121212121212121, 21212121212121212121212121, 2121212121212121212121212121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Index entries for linear recurrences with constant coefficients, signature (101,-100). FORMULA a(n) = (10^(2*n)-1)*21/99. MAPLE a:= n-> parse(cat(21\$n)): seq(a(n), n=1..20);  # Alois P. Heinz, Jun 16 2021 PROG (PARI) g2(n) = (10^(2*n)-1)*1*21/99 for(x=1, 25, print1(g2(x), ", ")) CROSSREFS Cf. A177090. Sequence in context: A265175 A300577 A304643 * A221771 A007593 A219104 Adjacent sequences:  A153845 A153846 A153847 * A153849 A153850 A153851 KEYWORD nonn,easy AUTHOR Cino Hilliard, Jan 02 2009 STATUS approved

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Last modified September 24 16:35 EDT 2021. Contains 347651 sequences. (Running on oeis4.)