ζ′⁡(-1,a)-112+14⁢a2-(112-12⁢a+12⁢a2)⁢ln⁡a∼-∑k=1∞B2⁢k+2(2⁢k+2)⁢(2⁢k+1)⁢2⁢k⁢a-2⁢k,