A161873 Bases with smallest happy number > 1 in that base equal to the base.

2, 3, 5, 6, 7, 8, 11, 12, 13, 14, 15, 17, 21, 22, 23, 24, 26, 27, 28, 31, 32, 33, 35, 38, 39, 40, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 54, 56, 57, 58, 59, 61, 62, 63, 65, 66, 67, 69, 70, 71, 72, 74, 75, 76, 77, 78, 79, 80, 82, 83, 84, 86, 87, 88, 89

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Mathematica

happyQ[n_, b_] := NestWhile[Plus @@ (IntegerDigits[#, b]^2) &, n, UnsameQ, All] == 1; seqQ[b_] := happyQ[b, b] && AllTrue[Range[2, b - 1], ! happyQ[#, b] &]; Select[Range[2, 100], seqQ] (* Amiram Eldar, May 28 2020 *)

Crossrefs

Cf. A007770 (happy numbers in base 10).

Sequence in context: A050942 A096600 A122686 * A224517 A341534 A080220

Adjacent sequences: A161870 A161871 A161872 * A161874 A161875 A161876

Keyword

nonn,base

Author

Jud McCranie, Jun 20 2009

Status

approved