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.

A350349 Lexicographically earliest increasing sequence of positive integers such that the Hankel matrix of any odd number of consecutive terms is invertible.

Original entry on oeis.org

1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 14, 15, 16, 17, 19, 20, 21, 22, 25, 26, 27, 28, 30, 31, 32, 33, 35, 36, 38, 39, 42, 43, 44, 45, 47, 48, 49, 50, 52, 53, 55, 56, 57, 58, 60, 61, 62, 63, 66, 67, 68, 69, 71, 72, 73, 74, 76, 77, 80, 81, 82, 83, 85, 86, 87, 88, 90
Offset: 1

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Author

Pontus von Brömssen, Dec 26 2021

Keywords

Crossrefs

Programs

  • Python
    from sympy import Matrix
    from itertools import count
    def A350349_list(nmax):
        a=[1]
        for n in range(1,nmax):
            a.append(next(k for k in count(a[-1]+1) if all(Matrix((n-r)//2+1,(n-r)//2+1,lambda i,j:(a[r:]+[k])[i+j]).det()!=0 for r in range(n-2,-1,-2))))
        return a