A166550 Numbers n with property that n^2 and n-th prime have the same sum of digits.

4, 8, 11, 22, 34, 59, 61, 85, 179, 229, 260, 266, 352, 385, 391, 403, 418, 440, 491, 565, 595, 619, 724, 770, 832, 844, 961, 965, 980, 1012, 1039, 1069, 1075, 1099, 1108, 1127, 1139, 1148, 1211, 1217, 1390, 1468, 1585, 1589, 1649, 1747, 1780, 1789, 1795, 1799

Offset

1,1

Comments

A007605(n)=A004159(n).

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

4^2=16, prime(4)=7, 1+6=7
8^2=64, prime(8)=19, 6+4=1+9
11^2=121, prime(11)=31, 1+2+1=3+1
22^2=484, prime(22)=79, 4+8+4=7+9
34^2=1156, prime(22)=139, 1+1+5+6=1+3+9.

Mathematica

Position[Table[Plus@@IntegerDigits[Prime[n]]-Plus@@IntegerDigits[n^2], {n, 1, 3000}], 0]//Flatten
Select[Range[2000], Total[IntegerDigits[#^2]]==Total[IntegerDigits[ Prime[ #]]]&] (* Harvey P. Dale, May 22 2015 *)

Crossrefs

Cf. A117224 Numbers for which the square and the cube have the same digital sum, A007605 Sum of digits of n-th prime, A004159 Sum of digits of n^2.

Sequence in context: A214970 A233188 A220753 * A219747 A032819 A181684

Adjacent sequences: A166547 A166548 A166549 * A166551 A166552 A166553

Keyword

base,nonn

Author

Zak Seidov, Oct 16 2009

Status

approved