A156614 a(1)=2, a(n+1) is the smallest prime with sum of even digits >= sum of even digits of a(n).

2, 23, 29, 41, 43, 47, 61, 67, 83, 89, 181, 263, 269, 281, 283, 461, 463, 467, 487, 661, 683, 863, 881, 883, 887, 1889, 2683, 2687, 2689, 2861, 2887, 4861, 4889, 6689, 6863, 6869, 6883, 8681, 8689, 8861, 8863, 8867, 8887, 26881

Offset

1,1

Comments

An increasing sequence of primes a(n) such that the sequence A071648(a(n)) is nondecreasing. - R. J. Mathar, May 15 2010

Links

Harvey P. Dale, Table of n, a(n) for n = 1..100

Example

2, 23(2=2), 29(2=2), 41(4>2), 43(4=4), 61(6>4), 67(6=6), 83(8>6), 89(8=8), 181(8=8), 263(2+6=8), 269(2+6=2+6), 281(2+8>2+6), 283(2+8=2+8), 461(4+6=2+8), etc.

Mathematica

t={}; max=0; Do[p=Prime[i]; If[(x=Total[Select[IntegerDigits[p], EvenQ[#] &]])>=max, max = x; AppendTo[t, p]], {i, 3000}]; t (* Jayanta Basu, May 22 2013 *)
sped[p_]:=Module[{d1=Total[Select[IntegerDigits[p], EvenQ]], p2=NextPrime[p]}, While[ Total[ Select[ IntegerDigits[ p2], EvenQ]]<d1, p2=NextPrime[p2]]; p2]; NestList[sped, 2, 50] (* or *) DeleteDuplicates[Table[{p, Total[Select[IntegerDigits[p], EvenQ]]}, {p, Prime[Range[ 3000]]}], Greater[ #1[[2]], #2[[2]]]&][[;; , 1]](* Harvey P. Dale, Jan 22 2024 *)

Crossrefs

Cf. A000040.

Sequence in context: A141533 A045391 A154758 * A355430 A226016 A235150

Adjacent sequences: A156611 A156612 A156613 * A156615 A156616 A156617

Keyword

nonn,base,less

Author

Juri-Stepan Gerasimov, Feb 11 2009

Extensions

Corrected (4861 inserted) by R. J. Mathar, May 15 2010

Status

approved