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A280915 Primes where difference between largest digit and all other digits is a positive square. 3
11, 23, 37, 43, 59, 67, 73, 89, 101, 113, 127, 131, 149, 157, 167, 179, 197, 211, 239, 241, 257, 263, 269, 271, 293, 307, 311, 337, 347, 359, 373, 419, 421, 431, 449, 461, 491, 509, 523, 541, 571, 593, 607, 617, 641, 719, 733, 743, 751, 761, 809, 853, 941, 953, 971, 1013, 1021, 1031 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
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.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
Prime 1153 is in a(n) since 5-3-1-1=0. Zero is square.
Prime 1163 is in a(n) since 6-3-1-1=1. One is square.
Prime 1171 is in a(n) since 7-1-1-1=4. Four is square.
MATHEMATICA
Select[Prime@ Range@ 175, IntegerQ@ Sqrt@ Fold[#1 - #2 &, Max@ #, Rest@ #] &@ Reverse@ Sort@ IntegerDigits@ # &] (* Michael De Vlieger, Feb 02 2017 *)
PROG
(PARI) is(n)=my(d=digits(n)); issquare(2*vecmax(d)-vecsum(d)) && isprime(n) \\ Charles R Greathouse IV, Feb 05 2017
CROSSREFS
This sequence is a parent sequence of A156753.
Sequence in context: A079664 A160268 A135978 * A139493 A275591 A250665
KEYWORD
nonn,base
AUTHOR
Osama Abuajamieh, Jan 10 2017
STATUS
approved

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Last modified March 2 07:45 EST 2024. Contains 370460 sequences. (Running on oeis4.)