You missed 39. The numbers up to 100 with digital root not a substring of their digit sum are (first column is the number, second is the digital root, third is the digit sum): 29 2 11 38 2 11 39 3 12 47 2 11 48 3 12 49 4 13 56 2 11 57 3 12 58 4 13 59 5 14 65 2 11 66 3 12 67 4 13 68 5 14 69 6 15 74 2 11 75 3 12 76 4 13 77 5 14 78 6 15 79 7 16 83 2 11 84 3 12 85 4 13 86 5 14 87 6 15 88 7 16 89 8 17 92 2 11 93 3 12 94 4 13 95 5 14 96 6 15 97 7 16 98 8 17 99 9 18 On Fri, Feb 28, 2020 at 10:31 AM Éric Angelini <eric.angelini@skynet.be> wrote:
Hello Math-Fun, are 29, 38, 47, 48 and 49 the first five integers whose digitroot is NOT a substring of the digitsum? Best, É. Catapulté de mon aPhone
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