A379208 Numbers k such that prime(k) and prime(k) + 9 are anagrams.

9, 19, 24, 26, 39, 48, 73, 77, 79, 91, 99, 110, 126, 143, 163, 188, 197, 200, 209, 212, 219, 224, 237, 241, 247, 252, 262, 269, 278, 279, 281, 285, 290, 291, 316, 336, 355, 360, 365, 391, 403, 405, 408, 431, 434, 439, 442, 448, 464, 468, 477, 486, 507, 517, 524, 531, 539, 544, 549, 550, 551, 575, 589, 602, 615

Offset: 1

Author

Vincenzo Librandi, Dec 18 2024

Keywords

• nonn
• base

Examples

			9 is a term of the sequence because prime(9) = 23 and 23 + 9 = 32 are anagrams.
		

Links

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

Crossrefs

Cf. A140353, A228157.

Programs

Magma

[n: n in [0..2000] | Sort(Intseq(NthPrime(n))) eq Sort(Intseq(NthPrime(n) + 9))];

Maple

filter:= proc(k) local p;
  p:= ithprime(k);
  sort(convert(p,base,10)) = sort(convert(p+9,base,10))
end proc:
select(filter, [$1..1000]); # Robert Israel, Jan 18 2025

Mathematica

Select[Range[3000],Sort[IntegerDigits[Prime[#]]]==Sort[IntegerDigits[Prime[#]+9]]&]

PARI

is(n) = my(p = prime(n)); vecsort(digits(p)) == vecsort(digits(p+9)) \\ David A. Corneth, Dec 18 2024

Extensions

Name corrected by David A. Corneth, Dec 18 2024