A143074 Numerator of Euler(n,2).
1, 3, 2, 9, 2, 3, 2, 33, 2, -27, 2, 699, 2, -5457, 2, 929601, 2, -3202287, 2, 221930589, 2, -4722116517, 2, 968383680843, 2, -14717667114147, 2, 2093660879252679, 2, -86125672563201177, 2, 129848163681107302017, 2, -868320396104950823607, 2, 209390615747646519456969
Offset: 0
Examples
By the formula, we have a(1) = 2*2 - 1 = 3, a(3) = 2*4 + 1 = 9, a(5) = 2*2 - 1 = 3, a(7) = 2*8 + 17 = 33, a(9) = 2*2 - 31 = -27, etc. - _Vladimir Shevelev_, Sep 04 2017
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..200
- Vladimir Shevelev, On a Luschny question, arXiv:1708.08096 [math.NT], 2017.
- Vladimir Shevelev, A formula for numerator of Euler(n,k), Wed Sep 06 2017.
Crossrefs
Programs
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Mathematica
Numerator[EulerE[Range[0,40],2]] (* Vincenzo Librandi, May 03 2012 *)
Formula
For even n, a(n) = 2 - delta(n,0), where delta is the Kronecker symbol;