cp's OEIS Frontend

A010349 Base-7 Armstrong or narcissistic numbers, written in base 7.

%I A010349 #35 Feb 16 2025 08:32:32
%S A010349 1,2,3,4,5,6,13,34,44,63,250,251,305,505,12205,12252,13350,13351,
%T A010349 15124,36034,205145,1424553,1433554,3126542,4355653,6515652,125543055,
%U A010349 161340144,254603255,336133614,542662326,565264226,13210652042,13213641035,13261421245,23662020022,52112660266
%N A010349 Base-7 Armstrong or narcissistic numbers, written in base 7.
%C A010349 From _M. F. Hasler_, Nov 20 2019: (Start)
%C A010349 Like the other single-digit terms, zero would satisfy the definition (n = Sum_{i=1..k} d[i]^k where d[1..k] are the base 7 digits of n), but here only positive numbers are considered.
%C A010349 Whenever a(n) ends in zero (n = 11, 17, 22, 38, 57), then a(n+1) = a(n) + 1 is also a solution to the above equation. (End)
%H A010349 Joseph Myers, <a href="/A010349/b010349.txt">Table of n, a(n) for n = 1..59</a> (the full list of terms, from Winter)
%H A010349 Gordon L. Miller and Mary T. Whalen, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/30-3/miller.pdf">Armstrong Numbers: 153 = 1^3 + 5^3 + 3^3</a>, Fibonacci Quarterly, 30-3 (1992), 221-224.
%H A010349 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/NarcissisticNumber.html">Narcissistic Number</a>
%H A010349 D. T. Winter, <a href="http://web.archive.org/web/20100109234250/http://ftp.cwi.nl:80/dik/Armstrong">Table of Armstrong Numbers</a> (latest backup on web.archive.org from Jan. 2010; page no longer available), published not later than Aug. 2003.
%o A010349 (PARI) [fromdigits(digits(n,7))|n<-A010350] \\ _M. F. Hasler_, Nov 18 2019
%Y A010349 Cf. A010350 (a(n) written in base 10).
%Y A010349 In other bases: A010343 (base 4), A010345 (base 5), A010347 (base 6), A010351 (base 8), A010352 (base 9), A005188 (base 10).
%K A010349 base,fini,full,nonn
%O A010349 1,2
%A A010349 _N. J. A. Sloane_
%E A010349 Edited by _Joseph Myers_, Jun 28 2009