A226531 -id:A226531 - cp's OEIS frontend

A265211 Squares that become prime when their rightmost digit is removed.

25, 36, 196, 676, 1936, 2116, 3136, 4096, 5476, 5776, 7396, 8836, 11236, 21316, 23716, 26896, 42436, 51076, 55696, 59536, 64516, 65536, 75076, 81796, 87616, 92416, 98596, 106276, 118336, 119716, 132496, 179776, 190096, 198916, 206116, 215296, 256036, 274576, 287296

Offset: 1

K. D. Bajpai, Dec 05 2015

All the terms in this sequence, except a(1) end in digit 6.
All the terms except a(2) are congruent to 1 (mod 3).
All terms except a(1) are of the form 10*p+6 where p is a prime of the form 10*x^2 + 8*x + 1 or 10*x^2 + 12*x + 3. The Bunyakovsky conjecture implies that there are infinitely many of both of these types. - Robert Israel, Jan 12 2016

			196 = 14^2 becomes the prime 19 when its rightmost digit is removed.
3136 = 56^2 becomes the prime 313 when its rightmost digit is removed.

K. D. Bajpai, Table of n, a(n) for n = 1..10000
Wikipedia, Bunyakovsky conjecture.

Cf. A000290, A225873, A225885, A226354, A226531.

[k: n in [1..100] | IsPrime(Floor(k/10)) where k is n^2];

select(t -> isprime(floor(t/10)), [seq(i^2, i=1..1000)]); # Robert Israel, Jan 12 2016

A265211 = {}; Do[k = n^2; If[PrimeQ[Floor[k/10]], AppendTo[A265211 , k]], {n, 1500}]; A265211
Select[Range[540]^2,PrimeQ[FromDigits[Most[IntegerDigits[#]]]]&] (* Harvey P. Dale, Aug 02 2016 *)

for(n=1,1000, k=n^2; if(isprime(k\10), print1(k, ", ")));

cp's OEIS Frontend

A265211 Squares that become prime when their rightmost digit is removed.

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