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.

A375203 Positions of records in A375202.

Original entry on oeis.org

0, 3, 12, 43, 48, 142, 172, 192, 427, 568, 688, 768, 1708, 2272, 2752, 3072, 6832, 9088, 11008, 12288, 27328, 36352, 44032, 49152, 109312, 145408, 176128, 196608, 437248, 581632, 704512, 786432, 1748992, 2326528, 2818048, 3145728, 6995968, 9306112, 11272192
Offset: 1

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Author

Robert Israel, Oct 15 2024

Keywords

Comments

Numbers k such that the A375202(k) > A375202(j) for all j < k.

Examples

			a(3) = 12 is a term because A375202(12) = 2 and A375202(j) <= 1 for j < 12.
		

Crossrefs

Programs

  • Maple
    f:= proc(n) local q,x,y,z;
      if n/4^padic:-ordp(n,4) mod 8 = 7 then return -1 fi;
      for x from 0 while 3*x^2 <= n do
        if [isolve(y^2 + z^2 = n - x^2)] <> [] then return x fi
      od;
    end proc:
    R:= NULL:count:= 0: m:= -1;
    for i from 0 while count < 39 do
      v:= f(i);
      if v > m then
        R:= R,i; m:= v; count:=count+1
      fi
    od:
    R;
  • Python
    from itertools import count, islice
    from math import isqrt
    from sympy import factorint
    def A375203_gen(): # generator of terms
        c = -1
        for n in count(0):
            v = (~n & n-1).bit_length()
            if v&1 or n>>v&7!=7:
                a = next(x for x in range(isqrt(n//3)+1) if not any(e&1 and p&3==3 for p, e in factorint(n-x**2).items()))
                if a>c:
                    yield n
                    c = a
    A375203_list = list(islice(A375203_gen(),20)) # Chai Wah Wu, Oct 16 2024

Formula

A375202(a(n)) = A375204(n).

Extensions

a(35)-a(39) from Chai Wah Wu, Oct 16 2024