This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A146561 #35 May 06 2025 10:59:03 %S A146561 1034482758620689655172413793,1379310344827586206896551724, %T A146561 1724137931034482758620689655,2068965517241379310344827586, %U A146561 2413793103448275862068965517,2758620689655172413793103448,3103448275862068965517241379,10344827586206896551724137931034482758620689655172413793 %N A146561 Numbers m with the property that shifting the rightmost digit of m to the left end multiplies the number by 3. %C A146561 For consistency with A146088 (analog for k=2), where an initial a(0) = 0 has been added, the same should be done here. - _M. F. Hasler_, May 03 2025 %H A146561 Seiichi Manyama, <a href="/A146561/b146561.txt">Table of n, a(n) for n = 1..245</a> %H A146561 Wikipedia, <a href="https://en.wikipedia.org/wiki/Parasitic_number">Parasitic number</a>. %F A146561 From _Seiichi Manyama_, Aug 22 2017: (Start) %F A146561 a(7*k - 6) = 3*(10^(28*k) - 1)/29. %F A146561 a(7*k - 5) = 4*(10^(28*k) - 1)/29. %F A146561 a(7*k - 4) = 5*(10^(28*k) - 1)/29. %F A146561 a(7*k - 3) = 6*(10^(28*k) - 1)/29. %F A146561 a(7*k - 2) = 7*(10^(28*k) - 1)/29. %F A146561 a(7*k - 1) = 8*(10^(28*k) - 1)/29. %F A146561 a(7*k) = 9*(10^(28*k) - 1)/29. (End) %Y A146561 Cf. A146088 (k=2), this sequence (k=3), A146569 (k=4), A146754 (k=5), A291354 (k=6), A291215 (k=7), A291321 (k=8), A291353 (k=9). %Y A146561 All these are subsequences of A034089. %Y A146561 Cf. A092697, A097717. %K A146561 nonn,base,easy %O A146561 1,1 %A A146561 _N. J. A. Sloane_, based on correspondence from William A. Hoffman III (whoff(AT)robill.com), Apr 10 2009 %E A146561 More terms from _Seiichi Manyama_, Aug 22 2017