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A280915 Primes where difference between largest digit and all other digits is a positive square. 3

%I

%S 11,23,37,43,59,67,73,89,101,113,127,131,149,157,167,179,197,211,239,

%T 241,257,263,269,271,293,307,311,337,347,359,373,419,421,431,449,461,

%U 491,509,523,541,571,593,607,617,641,719,733,743,751,761,809,853,941,953,971,1013,1021,1031

%N Primes where difference between largest digit and all other digits is a positive square.

%C If the largest digit L (say) is repeated, the criterion is that that L - (sum of all digits except for one copy of L) is a square.

%H Charles R Greathouse IV, <a href="/A280915/b280915.txt">Table of n, a(n) for n = 1..10000</a>

%e Prime 1153 is in a(n) since 5-3-1-1=0. Zero is square.

%e Prime 1163 is in a(n) since 6-3-1-1=1. One is square.

%e Prime 1171 is in a(n) since 7-1-1-1=4. Four is square.

%t Select[Prime@ Range@ 175, IntegerQ@ Sqrt@ Fold[#1 - #2 &, Max@ #, Rest@ #] &@ Reverse@ Sort@ IntegerDigits@ # &] (* _Michael De Vlieger_, Feb 02 2017 *)

%o (PARI) is(n)=my(d=digits(n)); issquare(2*vecmax(d)-vecsum(d)) && isprime(n) \\ _Charles R Greathouse IV_, Feb 05 2017

%Y This sequence is a parent sequence of A156753.

%K nonn,base

%O 1,1

%A _Osama Abuajamieh_, Jan 10 2017

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Last modified October 23 11:52 EDT 2021. Contains 348212 sequences. (Running on oeis4.)