cp's OEIS Frontend

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.

A037440 Positive numbers having the same set of digits in base 7 and base 10.

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%I A037440 #22 Apr 22 2023 14:28:56
%S A037440 1,2,3,4,5,6,23,46,265,316,1030,1234,1336,1366,1401,1431,1443,1454,
%T A037440 1464,2060,2116,3261,3515,3621,4631,5052,10144,10342,10542,11134,
%U A037440 11425,11524,11544,12415,12450,12532,12564,12651,13035,13045,13245
%N A037440 Positive numbers having the same set of digits in base 7 and base 10.
%H A037440 John Cerkan, <a href="/A037440/b037440.txt">Table of n, a(n) for n = 1..10000</a>
%e A037440 1336 is in the sequence because 1336 in base 7 is 3616.
%t A037440 Select[Range@ 13300, Union@ IntegerDigits@ # == Union@ IntegerDigits[#, 7] &] (* _Michael De Vlieger_, Feb 18 2017 *)
%o A037440 (PARI) isok(n) = Set(digits(n, 7)) == Set(digits(n)); \\ _Michel Marcus_, Feb 18 2017
%o A037440 (Python)
%o A037440 from sympy.ntheory import digits
%o A037440 def ok(n): return set(map(int, str(n))) == set(digits(n, 7)[1:])
%o A037440 print([k for k in range(1, 10**6) if ok(k)]) # _Michael S. Branicky_, Apr 22 2023
%Y A037440 Subsequence of A037404.
%Y A037440 Cf. A007093.
%K A037440 nonn,base
%O A037440 1,2
%A A037440 _Clark Kimberling_
%E A037440 More terms from _Don Reble_, Apr 28 2006
%E A037440 Edited by _John Cerkan_, Feb 17 2017