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A159254 Numbers n with property that n^2 ends with 49. 3
7, 43, 57, 93, 107, 143, 157, 193, 207, 243, 257, 293, 307, 343, 357, 393, 407, 443, 457, 493, 507, 543, 557, 593, 607, 643, 657, 693, 707, 743, 757, 793, 807, 843, 857, 893, 907, 943, 957, 993, 1007, 1043, 1057, 1093, 1107, 1143, 1157, 1193, 1207, 1243, 1257 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

First 7 terms = 7th row in A111445.

LINKS

Table of n, a(n) for n=1..51.

Index entries for linear recurrences with constant coefficients, signature (1,1,-1).

FORMULA

a(1)=7, a(2)=43, a(n)=50+a(n-2).

From Colin Barker, Jul 04 2014: (Start)

a(n) = (11*(-1)^n+50*n-25)/2.

a(n) = a(n-1)+a(n-2)-a(n-3).

G.f.: x*(7*x^2+36*x+7) / ((x-1)^2*(x+1)). (End)

PROG

(PARI) select(n->n^2%100==49, vector(10^3, n, n)) \\ Colin Barker, Jul 04 2014

CROSSREFS

A111445 Triangle read by rows: row n contains the first n numbers whose squares end in n^2.

Sequence in context: A175159 A173828 A045800 * A062336 A085704 A243459

Adjacent sequences:  A159251 A159252 A159253 * A159255 A159256 A159257

KEYWORD

base,nonn,easy

AUTHOR

Zak Seidov, Apr 07 2009

STATUS

approved

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Last modified July 20 11:28 EDT 2019. Contains 325180 sequences. (Running on oeis4.)