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A277717
Primes that only occur once in A094877.
1
3, 5, 7, 13, 19, 23, 29, 37, 43, 47, 61, 67, 71, 73, 79, 89, 97, 103, 109, 113, 151, 179, 181, 193, 211, 223, 233, 241, 277, 281, 283, 293, 307, 313, 331, 337, 347, 349, 359, 373, 379, 383, 397, 401, 409, 419, 421, 443, 449, 463, 467, 479, 487, 523, 557
OFFSET
1,1
COMMENTS
Primes n that are not k + A003132(k) for any nonprime k < n.
LINKS
MAPLE
N:= 1000: # to get the first N terms
res:= NULL: count := 0:
for n from 1 while count < N do
if isprime(n) then
if R[n] <> false then count:= count+1; res:= res, n fi
else
v:= n + add(t^2, t=convert(n, base, 10));
if isprime(v) then R[v]:= false fi;
fi
od:
res;
MATHEMATICA
With[{nn = 1200}, TakeWhile[#, # <= nn/2 &] &@ First@ Transpose@ TakeWhile[#, Last@ # == 1 &] &@ SortBy[#, Last] &@ Tally@ Array[NestWhile[# + Total[IntegerDigits[#]^2] &, #, ! PrimeQ@ # &] &, nn]] (* Michael De Vlieger, Oct 27 2016, after Harvey P. Dale at A094877 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert Israel, Oct 27 2016
STATUS
approved