Engel series expansion (or "Egyptian product") for Catalan's constant G.

Terms

a(0) =2a(1) =2a(2) =2a(3) =4a(4) =4a(5) =5a(6) =5a(7) =12a(8) =13a(9) =41a(10) =110a(11) =172a(12) =248a(13) =309a(14) =3146a(15) =5919a(16) =21959a(17) =22299a(18) =30892a(19) =401838a(20) =1719239a(21) =30576561a(22) =262313756a(23) =630913752a(24) =3242181301a(25) =3250783944a(26) =13827502849a(27) =40152067840a(28) =137791590233