A059755 - OEIS

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A059755

Odd rare numbers: odd n such that n-r and n+r are squares, where r is the reverse of n.

65, 868591084757, 6979302951885, 6157577986646405, 8052956026592517, 8052956206592517, 8650327689541457, 8650349867341457, 619431353040136925, 619631153042134925, 631688638047992345, 633288858025996145, 633488632647994145, 653488856225994125

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

There are 20 terms up to 10^22. - Shyam Sunder Gupta, Dec 14 2019

REFERENCES

Shyam Sunder Gupta, "Systematic computations of rare numbers", The Mathematics Education, Vol. XXXII, No. 3, 1998.

LINKS

Shyam Sunder Gupta, Table of n, a(n) for n = 1..20

C. Rivera, Prime Puzzles Page

Shyam Sunder Gupta, Rare Numbers

EXAMPLE

65-56 = 9 and 65 + 56 = 121 are both (perfect) squares.

CROSSREFS

Cf. A035519.

Sequence in context: A035519 A368189 A238842 * A215657 A157631 A085503

Adjacent sequences: A059752 A059753 A059754 * A059756 A059757 A059758

KEYWORD

nice,nonn,base

AUTHOR

Shyam Sunder Gupta, Feb 11 2001

STATUS

approved