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 A161873 Bases with smallest happy number > 1 in that base equal to the base. 2
 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 (list; graph; refs; listen; history; text; internal format)
 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 A080220 A028778 Adjacent sequences:  A161870 A161871 A161872 * A161874 A161875 A161876 KEYWORD nonn,base AUTHOR Jud McCranie, Jun 20 2009 STATUS approved

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Last modified January 27 01:45 EST 2021. Contains 340443 sequences. (Running on oeis4.)