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A092118 Biperiod squares: square numbers whose digits repeat twice in order. 3
1322314049613223140496, 2066115702520661157025, 2975206611629752066116, 4049586776940495867769, 5289256198452892561984, 6694214876166942148761, 8264462810082644628100, 183673469387755102041183673469387755102041 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

R. Ondrejka, Problem 1130: Biperiod Squares, Journal of Recreational Mathematics, Vol. 14:4 (1981-82), 299. Solution by F. H. Kierstead, Jr., JRM, Vol. 15:4 (1982-83), 311-312.

LINKS

Table of n, a(n) for n=1..8.

Author?, MMB message board "big square"

MAPLE

f:=proc(n) local i, j, k; i:=cat(n, n); j:=convert(i, decimal, 10); issqr(j); end;

with(numtheory): Digits:=50:for d from 1 to 22 do tendp1:=10^d+1: tendp1fact:=ifactors(tendp1)[2]: n:=mul(piecewise(tendp1fact[i][2] mod 2=1, tendp1fact[i][1], 1), i=1..nops(tendp1fact)):for i from ceil(sqrt((10^(d-1))/n)) to floor(sqrt((10^d-1)/n)) do printf("%d, ", tendp1*n*i^2) od: od: # C. Ronaldo

CROSSREFS

Cf. A102567, A106497.

Sequence in context: A095438 A115503 A280299 * A257376 A037017 A076335

Adjacent sequences:  A092115 A092116 A092117 * A092119 A092120 A092121

KEYWORD

base,nonn

AUTHOR

Michael Mark, Dec 15 2004

EXTENSIONS

Corrected and extended by C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 15 2005

Definition corrected and improved, reference and cross-reference added by William Rex Marshall, Nov 12 2010

Keyword base added by William Rex Marshall, Nov 12 2010

STATUS

approved

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Last modified November 20 03:25 EST 2018. Contains 317371 sequences. (Running on oeis4.)