login
A274932
Squares n = k^2 with the property that nextprime(k) is a substring of n.
3
529, 729, 6889, 12769, 162409, 644809, 851929, 1261129, 47969476, 64048009, 317837584, 1600240009, 2822053129, 24421563076, 40001200009, 84290347584, 107667328129, 145381301521, 160002400009, 437766166321, 788815751409
OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..39 (all terms < 4*10^18)
EXAMPLE
529 = 23^2, and nextprime(23) = 29 is a substring of 529, so 529 is a term.
MATHEMATICA
Select[Range[2*10^6]^2, SequenceCount[IntegerDigits[#], IntegerDigits[ NextPrime[ Sqrt[ #]]]]>0&] (* The program uses the SequenceCount function from Mathematica version 10 *) (* Harvey P. Dale, Jul 13 2016 *)
Select[Range[2*10^6], {} != StringPosition @@ ToString /@ {#^2, NextPrime@ #} &]^2] (* Giovanni Resta, Jul 15 2016 *)
CROSSREFS
Suggested by A052074.
Sequence in context: A339636 A181414 A020289 * A082409 A066742 A067475
KEYWORD
nonn,base
AUTHOR
STATUS
approved