a(n) is the number whose base-4 digits are 1 followed by the first n-1 terms of the periodic sequence with initial period 0,3,2.

A378499

a(n) is the number whose base-4 digits are 1 followed by the first n-1 terms of the periodic sequence with initial period 0,3,2.

Terms

    a(0) =1a(1) =4a(2) =19a(3) =78a(4) =312a(5) =1251a(6) =5006a(7) =20024a(8) =80099a(9) =320398a(10) =1281592a(11) =5126371a(12) =20505486a(13) =82021944a(14) =328087779a(15) =1312351118a(16) =5249404472a(17) =20997617891a(18) =83990471566a(19) =335961886264

External references