A048392 -id:A048392 - cp's OEIS frontend

A048390 Digits d in decimal expansion of n replaced with d^3.

0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 10, 11, 18, 127, 164, 1125, 1216, 1343, 1512, 1729, 80, 81, 88, 827, 864, 8125, 8216, 8343, 8512, 8729, 270, 271, 278, 2727, 2764, 27125, 27216, 27343, 27512, 27729, 640, 641, 648, 6427, 6464, 64125, 64216, 64343

Offset: 0

Patrick De Geest, Mar 15 1999

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Cf. A048391, A048392, A048393, A048394.

[0] cat [StringToInteger(&cat[IntegerToString(h): h in Reverse([i^3: i in Intseq(n)])]): n in [1..50]]; // Vincenzo Librandi, Mar 12 2013

FromDigits[Flatten[IntegerDigits/@(IntegerDigits[#]^3)]]&/@ Range[0,50] (* Harvey P. Dale, Jun 04 2011 *)

a(n) = my(d = digits(n)); my(s = ""); for (k=1, #d, s = concat(s, Str(d[k]^3))); eval(s); \\ Michel Marcus, Nov 06 2016

A048391 Replacing digits d in decimal expansion of n with d^3 yields a square.

Original entry on oeis.org

0, 1, 4, 9, 21, 100, 400, 561, 900, 2100, 8821, 10000, 11221, 17821, 40000, 56100, 73221, 90000, 210000, 211201, 518041, 882100, 1000000, 1001614, 1002621, 1012021, 1012224, 1122100, 1302801, 1782100, 4000000, 5012214, 5610000

Offset: 1

Patrick De Geest, Mar 15 1999

			E.g. 518041 = (5)(1)(8)(0)(4)(1) -> (125)(1)(512)(0)(64)(1) = 12515120641 = 111871^2 and a square.

Cf. A048390, A048392.

Select[Range[0,561*10^4],IntegerQ[Sqrt[FromDigits[Flatten[ IntegerDigits/@ (IntegerDigits[ #]^3)]]]]&] (* Harvey P. Dale, Apr 15 2019 *)

ccd(n) = {if (n==0, return(0)); my(d = digits(n)); my(nd = ""); for (i=1, #d, nd = Str(nd, d[i]^3);); eval(nd);}
isok(n) = issquare(ccd(n)); \\ Michel Marcus, Oct 19 2016

Offset corrected by Michel Marcus, Oct 19 2016

cp's OEIS Frontend

A048390 Digits d in decimal expansion of n replaced with d^3.

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