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A239992 Primes formed by concatenating a square number S with S+1, where S+1 is a prime number. 1
3637, 576577, 2433624337, 3240032401, 4410044101, 6969669697, 352836352837, 404496404497, 746496746497, 16641001664101, 17424001742401, 20050562005057, 20736002073601, 24523562452357, 26049962604997, 28022762802277, 34596003459601, 35494563549457, 42600964260097 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

It is observed that each term in the sequence ends either with digit 1 or 7.

LINKS

K. D. Bajpai, Table of n, a(n) for n = 1..1060

EXAMPLE

3637 is a prime formed by concatenaing 36 with 37 where 36= 6^2 and (36+1)= 37 is a prime.

576577 is a prime formed by concatenaing 576 with 577 where 576= 24^2 and (576+1)= 577 is a prime.

MAPLE

with(StringTools):KD := proc() local a, b, s; s:=n*n; b:=s+1; if isprime(b) then a:= parse(cat(s, b )); if isprime(a) then RETURN (a); fi; fi; end: seq(KD(), n=1..5000);

CROSSREFS

Cf. A000040, A030458.

Sequence in context: A206836 A206898 A207288 * A253498 A253491 A253452

Adjacent sequences:  A239989 A239990 A239991 * A239993 A239994 A239995

KEYWORD

nonn,base

AUTHOR

K. D. Bajpai, Mar 30 2014

STATUS

approved

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Last modified January 25 19:00 EST 2022. Contains 350572 sequences. (Running on oeis4.)