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A045856 Numbers whose square has initial digit '2'. 2
5, 15, 16, 17, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 448, 449, 450, 451, 452, 453, 454, 455, 456 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
Select[Range[500], IntegerDigits[#^2][[1]]==2&] (* Harvey P. Dale, Apr 15 2024 *)
PROG
(PARI) isok(n) = digits(n^2)[1] == 2; \\ Michel Marcus, May 28 2017
CROSSREFS
Sequence in context: A184288 A015666 A291627 * A102185 A030486 A101238
KEYWORD
nonn,base,changed
AUTHOR
EXTENSIONS
Corrected by Seiichi Manyama, May 28 2017
STATUS
approved

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Last modified April 17 15:33 EDT 2024. Contains 371764 sequences. (Running on oeis4.)