A092595 Numbers k such that the sum of decimal digits of k and k+1 are both prime numbers, i.e., both k and k+1 are in A028834.

2, 11, 20, 29, 49, 101, 110, 119, 139, 199, 200, 209, 229, 289, 319, 379, 409, 469, 559, 649, 739, 829, 919, 1001, 1010, 1019, 1039, 1099, 1100, 1109, 1129, 1189, 1219, 1279, 1309, 1369, 1459, 1549, 1639, 1729, 1819, 1909, 2000, 2009, 2029, 2089, 2119, 2179

Offset

1,1

Links

J.W.L. (Jan) Eerland, Table of n, a(n) for n = 1..10000.

Example

For k=4429, digitsum(k) = 4 + 4 + 2 + 9 = 19, digitsum(k+1) = 4 + 4 + 3 + 0 = 11.

Mathematica

t=Table[0, {256}]; j=1; Do[s=Apply[Plus, IntegerDigits[n]]; s1=Apply[Plus, IntegerDigits[n+1]]; If[PrimeQ[s]&&PrimeQ[s1], Print[n]; t[[j]]=n; j=j+1], {n, 1, 10000}]; t
DeleteCases[ParallelTable[If[PrimeQ[Total[IntegerDigits[n]]]&&PrimeQ[Total[IntegerDigits[n+1]]], n, a], {n, 2, 952999}], a] (* J.W.L. (Jan) Eerland, Dec 20 2021 *)

Prog

(PARI) isok(n) = isprime(sumdigits(n)) && isprime(sumdigits(n+1)); \\ Michel Marcus, Jul 29 2017

Crossrefs

Cf. A028834.

Sequence in context: A159879 A017185 A279774 * A175927 A116990 A327264

Adjacent sequences: A092592 A092593 A092594 * A092596 A092597 A092598

Keyword

base,nonn

Author

Labos Elemer, Mar 17 2004

Status

approved