Fermat coefficients.

Terms

a(0) =1a(1) =15a(2) =99a(3) =429a(4) =1430a(5) =3978a(6) =9690a(7) =21318a(8) =43263a(9) =82225a(10) =148005a(11) =254475a(12) =420732a(13) =672452a(14) =1043460a(15) =1577532a(16) =2330445a(17) =3372291a(18) =4790071a(19) =6690585a(20) =9203634a(21) =12485550a(22) =16723070a(23) =22137570a(24) =28989675a(25) =37584261a(26) =48275865a(27) =61474519a(28) =77652024a(29) =97348680