A277717 Primes that only occur once in A094877.

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

Robert Israel, Table of n, a(n) for n = 1..10000

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

Cf. A003132, A094830, A094877.

Sequence in context: A164642 A247633 A357170 * A120460 A127459 A174635

Adjacent sequences: A277714 A277715 A277716 * A277718 A277719 A277720

Keyword

nonn,base

Author

Robert Israel, Oct 27 2016

Status

approved