A232268 Numbers n such that reversal (n^3) plus 1 is prime.
1, 3, 4, 6, 10, 19, 28, 30, 31, 40, 60, 63, 64, 66, 87, 88, 93, 96, 100, 129, 132, 135, 138, 141, 144, 184, 190, 274, 279, 280, 283, 285, 292, 294, 297, 300, 303, 310, 393, 399, 400, 402, 433, 436, 439, 589, 597, 598, 600, 612, 616, 621, 628, 630, 639, 640, 642
Offset: 1
Examples
a(3)= 4: 4^3= 64: reversing the digits gives 46: 46+1= 47 which is prime. a(4)= 6: 6^3= 216: reversing the digits gives 612: 612+1= 613 which is prime. a(12)= 63: 63^3= 250047: reversing the digits gives 740052: 740052+1= 740053 which is prime.
Links
- K. D. Bajpai, Table of n, a(n) for n = 1..10000
Crossrefs
Programs
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Maple
with(StringTools): KD:= proc() local a; a:= parse(Reverse(convert((n^3), string)))+1; if isprime(a) then RETURN (n): fi;end: seq(KD(), n=1..5000);
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Mathematica
Select[Range[500],PrimeQ[ToExpression[StringReverse[ToString[#^3]]] + 1] &]
Comments