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A166550 Numbers n with property that n^2 and n-th prime have the same sum of digits. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified July 4 22:15 EDT 2020. Contains 335449 sequences. (Running on oeis4.)