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A249971 Numbers whose squares remain squares when prepended with 5 and appended with 25 in base 10. 5
16, 30730, 3727084, 3127636818781854350, 7536101752216453484, 52452254824270668843034, 260517421591511559294554416, 20815875053039440273965644350185324640 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

30730^2 = 944332900, 594433290025 = 770995^2.

PROG

(PARI) isok(n) = issquare(eval(concat(5, concat(Str(n^2), 25)))); \\ Michel Marcus, Nov 20 2014

CROSSREFS

Cf. A249968, A249969, A249970.

Sequence in context: A017416 A265618 A087518 * A221244 A280656 A265662

Adjacent sequences:  A249968 A249969 A249970 * A249972 A249973 A249974

KEYWORD

nonn,base

AUTHOR

Chai Wah Wu, Nov 19 2014

STATUS

approved

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Last modified July 29 06:36 EDT 2021. Contains 346340 sequences. (Running on oeis4.)