A340634 Numbers k such that k + A037276(k) is prime.

1, 6, 14, 18, 22, 26, 34, 36, 38, 46, 48, 62, 66, 74, 106, 108, 110, 122, 134, 146, 156, 166, 170, 174, 178, 194, 196, 198, 206, 226, 230, 254, 262, 274, 278, 290, 294, 298, 306, 318, 354, 362, 374, 386, 392, 394, 416, 420, 422, 426, 458, 466, 468, 490, 502, 504, 516, 526, 528, 530, 532, 544, 562

Offset

1,2

Comments

All terms except 1 are even.

Links

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

Example

a(3) = 14 is a term because 14 + A037276(14) = 14 + 27 = 41 is prime.

Maple

dcat:= proc(L) local i, x;
  x:= L[-1];
  for i from nops(L)-1 to 1 by -1 do
    x:= 10^(1+ilog10(x))*L[i]+x
  od;
  x
end proc:
A037276:= proc(n) local F;
  F:= sort(ifactors(n)[2], (a, b) -> a[1] < b[1]);
  dcat(map(t -> t[1]$t[2], F));
end proc:
A037276(1):= 1:
select(t -> isprime(t + A037276(t)), [1, seq(i, i=3..1000)]);

Crossrefs

Cf. A037276, A340633, A340636.

Sequence in context: A141082 A108977 A260114 * A156858 A032500 A053474

Adjacent sequences: A340631 A340632 A340633 * A340635 A340636 A340637

Keyword

nonn,base

Author

J. M. Bergot and Robert Israel, Jan 14 2021

Status

approved