A167608 Digit sum of cousin prime pairs.

10, 9, 12, 15, 15, 18, 21, 27, 18, 12, 15, 15, 24, 30, 18, 21, 27, 15, 18, 27, 33, 24, 27, 27, 30, 33, 30, 24, 30, 36, 33, 33, 39, 30, 36, 39, 39, 42, 27, 33, 39, 15, 27, 30, 18, 33, 24, 18, 24, 27, 27, 36, 39, 33, 33, 39, 30, 27, 36, 42, 42, 39, 42, 48, 33, 30, 21, 18, 27, 33, 36, 27, 33, 39, 27, 36, 33, 27, 39

Offset

1,1

Comments

Except for the first term, all the others are multiples of 3.

There is only one instance of cousin primes having a third prime in between them: 3, 5, 7. All other cousin primes are also consecutive primes. - Harvey P. Dale, Aug 21 2025

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..5000

Eric Weisstein's World of Mathematics, Cousin Primes

Example

The digit sum of the cousin prime pairs 223 and 227 is: 2+2+3+2+2+7 = 18.

Mathematica

cptot[n_]:=Total[Join[IntegerDigits[n], IntegerDigits[n+4]]]; cptot/@Select[ Prime[Range[500]], PrimeQ[#+4]&] (* Harvey P. Dale, Apr 27 2014 *)
Join[{10}, Total[Flatten[IntegerDigits/@#]]&/@Select[Partition[Prime[Range[500]], 2, 1], #[[2]]-#[[1]]==4&]] (* Harvey P. Dale, Aug 21 2025 *)

Crossrefs

Cf. A023200, A166173, A167607

Sequence in context: A231471 A063661 A154533 * A063596 A360382 A284518

Adjacent sequences: A167605 A167606 A167607 * A167609 A167610 A167611

Keyword

base,nonn

Author

Parthasarathy Nambi, Nov 07 2009

Status

approved