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A223035 Prime numbers whose digits squared sum to a square. 2
2, 3, 5, 7, 43, 263, 269, 1153, 1531, 1933, 2063, 2069, 2287, 2609, 3319, 3391, 3511, 3931, 4003, 4441, 4801, 4889, 5113, 5399, 5939, 6029, 6067, 6203, 6469, 6607, 8849, 9133, 9539, 10111, 10177, 10513, 10531, 10771, 11149, 11213, 11273, 11321, 11491, 11503 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Christian N. K. Anderson, Table of n, a(n) for n = 1..10000

EXAMPLE

269 is a prime number, and 2^2+6^2+9^2 = 121 = 11^2.

MATHEMATICA

Select[Prime[Range[2000]], IntegerQ[Sqrt[Total[IntegerDigits[#]^2]]] &] (* T. D. Noe, Apr 05 2013 *)

PROG

(R) ssod<-function(i) sum(as.numeric(strsplit(as.character(i), "")[[1]])^2)

issquare<-function(x) as.integer(sqrt(x))==sqrt(x)

x=as.bigz(c()); i=2

while(length(x)<10000) {if(issquare(ssod(i))) x=c(x, i); i=nextprime(i)}

CROSSREFS

Prime numbers from the sequence A175396.

Cf. A000040, A061910, A107288.

Sequence in context: A092066 A224904 A028981 * A096843 A052016 A171020

Adjacent sequences:  A223032 A223033 A223034 * A223036 A223037 A223038

KEYWORD

nonn,base

AUTHOR

Kevin L. Schwartz and Christian N. K. Anderson, Apr 04 2013

STATUS

approved

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Last modified October 15 10:15 EDT 2019. Contains 328026 sequences. (Running on oeis4.)