A069656 Perfect powers that can be permuted into another perfect power (in base 10).

125, 144, 169, 196, 243, 256, 324, 441, 512, 625, 961, 1024, 1089, 1296, 1369, 1728, 1764, 1936, 2187, 2197, 2401, 2916, 4096, 4761, 7921, 9216, 9261, 9604, 9801, 10201, 10404, 10609, 11236, 11664, 12100, 12544, 12769, 13689, 14400, 14884, 15129, 16384, 16641, 16807

Offset

1,1

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

Example

1024 = 2^10 and a digit permutation gives 2401 = 7^4.
1369 = 37^2 and a digit permutation gives 1936 = 44^2

Prog

(PARI) upto(n) = {l = List(); res = List(); for(i = 2, sqrtint(n), if(!ispower(i), for(j = 2, logint(n, i), c = i^j; listput(l, [freqdigits(c), c]); ) ) ); listsort(l, 1); for(i = 1, #l - 1, if(l[i][1] == l[i+1][1], k = i+1; while(k <= #l && l[i][1] == l[k][1], k++; ); for(j = i, k-1, listput(res, l[j][2]) ); ) ); listsort(res, 1); res }
addhelp(freqdigits, "Gives a vector that lists for every digit how often it occurs.") freqdigits(n) = {my(v=vector(10), d=digits(n)); for(i=1, #d, v[d[i]+1]++); v } \\ David A. Corneth, Aug 20 2020

Crossrefs

Cf. A001597.

Sequence in context: A115938 A126895 A202240 * A196943 A307386 A307515

Adjacent sequences: A069653 A069654 A069655 * A069657 A069658 A069659

Keyword

nonn,base

Author

Amarnath Murthy, Apr 04 2002

Extensions

Corrected and extended by Bodo Zinser, Apr 03 2005

Better definition from Jon Wild, Aug 20 2020

More terms from David A. Corneth, Aug 20 2020

Status

approved