Pseudo-powers to base 3: numbers k that are not powers of 3 such that k divides 2^k + 1.

Terms

a(0) =171a(1) =513a(2) =1539a(3) =3249a(4) =4617a(5) =9747a(6) =13203a(7) =13851a(8) =29241a(9) =39609a(10) =41553a(11) =61731a(12) =87723a(13) =97641a(14) =118827a(15) =124659a(16) =185193a(17) =250857a(18) =263169a(19) =292923a(20) =354537a(21) =356481a(22) =373977a(23) =555579a(24) =752571a(25) =789507a(26) =878769a(27) =1063611a(28) =1069443a(29) =1121931