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A225151 Squares which are a decimal concatenation of triprimes.

%I A225151 #16 May 03 2013 20:57:58
%S A225151 12544,15376,19044,20164,27556,28561,42436,45369,45796,75076,81796,
%T A225151 86436,87025,89401,98596,114244,116964,123201,124609,125316,126025,
%U A225151 127449,128164,131044,139876,141376,150544,174724,175561,184041,188356,190969,191844,207025
%N A225151 Squares which are a decimal concatenation of triprimes.
%H A225151 Christian N. K. Anderson, <a href="/A225151/b225151.txt">Table of n, a(n) for n = 1..10000</a>
%H A225151 Christian N. K. Anderson, <a href="/A225151/a225151.txt">Table of n, a(n), sqrt(a(n)), all possible separations of a(n) into triprimes</a>
%e A225151 a(10) is 75076, which splits into 75|076. 75 = 3*5*5; 76 = 2*2*19.
%o A225151 (R) library(gmp); istriprime=function(x) ifelse(x<8, F, length(factorize(x))==3)
%o A225151 splithasproperty<-function(n, FUN, curdig=1, res=list(), curspl=c()) {
%o A225151 no0<-function(s){ while(substr(s, 1, 1)=="0" & nchar(s)>1) s=substr(s, 2, nchar(s)); s}
%o A225151     s=as.character(n)
%o A225151     if(curdig>nchar(s)) return(res)
%o A225151     if(length(curspl)>0) if(FUN(as.bigz(no0(substr(s, curdig, nchar(s)))))) res[[length(res)+1]]=curspl
%o A225151     for(i in curdig:nchar(s))
%o A225151         if(FUN(as.bigz(no0(substr(s, curdig, i)))))
%o A225151             res=splithasproperty(n, FUN, i+1, res, c(curspl, i))
%o A225151     res
%o A225151 }
%o A225151 which(sapply(1:500, function(x) length(splithasproperty(x^2, istriprime)))>0)^2
%Y A225151 Cf. A014612, A030459, A030461, A000290, A019547.
%K A225151 nonn,base
%O A225151 1,1
%A A225151 _Kevin L. Schwartz_ and _Christian N. K. Anderson_, Apr 30 2013