

A059755


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


2



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

6556 = 9 and 65 + 56 = 121 are both (perfect) squares.


CROSSREFS

Cf. A035519.
Sequence in context: A185823 A035519 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



