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A159815 Numbers n with property that n^2 starts and ends with 49. 1
7, 707, 7007, 7043, 7057, 22143, 22157, 22193, 22207, 22243, 22257, 22293, 22307, 22343, 22357, 70007, 70043, 70057, 70093, 70107, 70143, 70157, 70193, 70207, 70243, 70257, 70293, 70307, 70343, 70357, 70393, 70407, 70443, 70457, 70493 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Most first differences are alternatively 14 and 36.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

{7,707,7007,7043,7057,22143,22157}^2={49,499849,49098049,49603849,49801249,490312449,490932649}.

MATHEMATICA

s7={}; Do[If[Take[IntegerDigits[n^2], 2]=={4, 9}&&PowerMod[n, 2, 100]==49, AppendTo[s7, n]], {n, 7, 300000}]; s7

se49Q[n_]:=Module[{id=IntegerDigits[n^2]}, Take[id, 2]==Take[id, -2] == {4, 9}]; Select[Range[5, 71000], se49Q] (* Harvey P. Dale, Apr 22 2016 *)

CROSSREFS

A159775 Numbers n with property that n^2 starts and ends with 81. A159754 Numbers n with property that n^2 ends with 81. A159254 Numbers n with property that n^2 ends with 49. A111445 n-th row contains first n numbers whose squares end in n^2.

Sequence in context: A186160 A129291 A229149 * A070746 A068004 A098110

Adjacent sequences:  A159812 A159813 A159814 * A159816 A159817 A159818

KEYWORD

base,nonn

AUTHOR

Zak Seidov, Apr 22 2009

STATUS

approved

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Last modified September 22 17:39 EDT 2021. Contains 347607 sequences. (Running on oeis4.)