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.

A367629 a(n) = 2^2^(n + 1) - 2^(n + 2).

Original entry on oeis.org

8, 240, 65504, 4294967232, 18446744073709551488, 340282366920938463463374607431768211200, 115792089237316195423570985008687907853269984665640564039457584007913129639424
Offset: 1

Views

Author

J Gregory Moxness, Nov 24 2023

Keywords

Comments

a(n) is the absolute value totals of the characteristic polynomial coefficients of n-qubit normalized Hadamard matrices, excluding the 2nd and next-to-last nonzero entries.
a(n) is also the total of the entries in row 2^(n+1) of Pascal's triangle (A007318), excluding the 2nd and next-to-last entries.

Crossrefs

Programs

  • Mathematica
    Table[2^2^(n+1)-2^(n+2),{n,10}] (* Harvey P. Dale, Aug 23 2024 *)
  • Python
    def A367629(n): return (1<<(m:=1<Chai Wah Wu, Nov 29 2023

Formula

a(n) = A107584(2^n).

Extensions

Previous Mathematica program replaced by Harvey P. Dale, Aug 23 2024