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.

A273663 Least monotonic left inverse for A273670: a(1) = 0; for n > 1, a(n) = A257680(A225901(n)) + a(n-1).

Original entry on oeis.org

0, 0, 1, 2, 3, 3, 4, 4, 5, 6, 7, 7, 8, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 17, 18, 18, 19, 20, 21, 21, 22, 22, 23, 24, 25, 25, 26, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 35, 36, 36, 37, 38, 39, 39, 40, 40, 41, 42, 43, 43, 44, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 53, 54, 54, 55, 56, 57, 57, 58, 58, 59, 60, 61, 61
Offset: 1

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Author

Antti Karttunen, May 30 2016

Keywords

Crossrefs

Left inverse of A273670.
Cf. also A273662.

Programs

  • Python
    from sympy import factorial as f
    def a007623(n, p=2): return n if n

Formula

a(1) = 0; for n > 1, a(n) = A257680(A225901(n)) + a(n-1).
Other identities.
For all n >= 0, a(A273670(n)) = n.