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.

A356150 a(n) is the sum of the positive integers whose binary expansion appears as a substring in the binary expansion of n or its complement.

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%I A356150 #10 Jul 31 2022 19:54:18
%S A356150 1,3,4,10,8,12,11,25,25,18,26,28,30,33,26,56,62,61,56,56,39,63,64,67,
%T A356150 62,66,72,77,80,78,57,119,139,143,137,135,134,119,134,134,134,81,120,
%U A356150 138,139,147,142,146,147,148,132,153,140,157,165,165,168,174,181
%N A356150 a(n) is the sum of the positive integers whose binary expansion appears as a substring in the binary expansion of n or its complement.
%C A356150 Leading 0's in binary expansions are ignored.
%H A356150 Rémy Sigrist, <a href="/A356150/b356150.txt">Table of n, a(n) for n = 1..8192</a>
%H A356150 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A356150 a(n) >= A078823(n).
%F A356150 a(n) Sum_{k = 1..A356148(n)} A356149(n, k).
%e A356150 For n = 11:
%e A356150 - row 11 of A356149 is 1, 2, 3, 4, 5, 11,
%e A356150 - so a(11) = 1 + 2 + 3 + 4 + 5 + 11 = 26.
%o A356150 (PARI) a(n) = { my (b=binary(n)); vecsum(setbinop((i,j) -> my (s=fromdigits(b[i..j],2)); if (b[i], s, 2^(j-i+1)-1-s), [1..#b])) }
%o A356150 (Python)
%o A356150 def a(n):
%o A356150     N = n.bit_length()
%o A356150     c, s = ((1<<N)-1)^n, set()
%o A356150     for i in range(N):
%o A356150         for l in range(N-i):
%o A356150             mask = ((2<<l)-1) << i
%o A356150             s.add((mask&n) >> i)
%o A356150             s.add((mask&c) >> i)
%o A356150     return sum(s)
%o A356150 print([a(n) for n in range(1, 60)]) # _Michael S. Branicky_, Jul 28 2022
%Y A356150 Cf. A078823, A356148, A356149.
%K A356150 nonn,base
%O A356150 1,2
%A A356150 _Rémy Sigrist_, Jul 28 2022