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 A290647 a(n) is the position of first occurrence of n^2 in the concatenation of the positive integers in decimal representation. 2
 1, 4, 9, 22, 40, 62, 88, 83, 27, 190, 14, 322, 397, 478, 565, 658, 757, 37, 299, 1090, 323, 86, 777, 141, 660, 124, 783, 1325, 443, 2590, 479, 2986, 3246, 3514, 3790, 4074, 4366, 4666, 346, 5290, 394, 5946, 6286, 6634, 6990, 3541, 7261, 8106, 3851, 8890, 3931, 9706, 10126, 5408, 9012, 4345, 8865, 981, 4283, 13290, 4379 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Zhining Yang, Table of n, a(n) for n = 1..1000 EXAMPLE s=123456789101112131415161718192021222324252627282930313233343536... a(4)=22 because the first occurrence of 4^2 = 16 in s starts at the 22nd digit. MATHEMATICA t = ""; k = 0; Table[ While[(z = StringPosition[t, ToString[n^2], 1]) == {}, t = t <> ToString[++k]]; z[[1, 1]], {n, 61}] (* Giovanni Resta, Aug 11 2017 *) PROG (VBA) Sub test() Dim i&, t\$ For i = 1 To 10000 t = t & i Next For i = 1 To 100 Debug.Print InStr(t, i ^ 2); ", "; Next End Sub CROSSREFS Cf. A031297, A290787. Sequence in context: A041743 A041943 A158140 * A105314 A200155 A002835 Adjacent sequences:  A290644 A290645 A290646 * A290648 A290649 A290650 KEYWORD nonn,base AUTHOR Zhining Yang, Aug 08 2017 STATUS approved

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Last modified September 22 03:21 EDT 2020. Contains 337289 sequences. (Running on oeis4.)