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 A289287 Starting with a(1) = 1, a(n) = smallest nonnegative integer not yet in the sequence such that the last digit of a(n-1) plus the first digit of a(n) is equal to 9. The digit 0 is not allowed. 2
 1, 8, 11, 81, 82, 7, 2, 71, 83, 6, 3, 61, 84, 5, 4, 51, 85, 41, 86, 31, 87, 21, 88, 12, 72, 73, 62, 74, 52, 75, 42, 76, 32, 77, 22, 78, 13, 63, 64, 53, 65, 43, 66, 33, 67, 23, 68, 14, 54, 55, 44, 56, 34, 57, 24, 58, 15, 45, 46, 35, 47, 25, 48, 16, 36, 37, 26, 38, 17, 27, 28, 18, 19 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The number of terms of this finite sequence is the ninth central polygonal number, n = 73. LINKS MATHEMATICA Module[{a = {1}, k, d = 9}, TimeConstrained[Do[k = 2; While[Or[MemberQ[a, k], MemberQ[IntegerDigits@ k, 0], # != d] &[Mod[a[[n - 1]], 10] + First@ IntegerDigits@ k], k++]; AppendTo[a, k], {n, 2, 100}], 2]; a] (* Michael De Vlieger, Jul 14 2017 *) CROSSREFS Cf. A002061, A289283, A289284, A289285, A289286. Sequence in context: A000787 A188000 A167621 * A006072 A196173 A074042 Adjacent sequences:  A289284 A289285 A289286 * A289288 A289289 A289290 KEYWORD nonn,base,fini,full AUTHOR Enrique Navarrete, Jul 01 2017 STATUS approved

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Last modified October 23 06:29 EDT 2018. Contains 316520 sequences. (Running on oeis4.)