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A095976 Numbers n such that (largest digit of n) + (largest digit of n+1) is prime. 1
1, 2, 3, 5, 6, 8, 10, 11, 12, 13, 15, 16, 18, 19, 22, 23, 25, 26, 28, 33, 35, 36, 38, 39, 45, 46, 48, 55, 56, 58, 66, 68, 78, 79, 88, 100, 101, 102, 103, 105, 106, 108, 110, 111, 112, 113, 115, 116, 118, 119, 122, 123, 125, 126, 128, 133, 135, 136, 138, 139, 145, 146 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

No terms contain digit 9 before a non-9. - Robert Israel, May 20 2020

LINKS

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

EXAMPLE

12348 is in the sequence because its largest digit 8, plus 9 the largest digit of 12349, is the prime 17.

MAPLE

N:= 500: # to get terms <= N

L:= map(t -> max(convert(t, base, 10)), [$1..N+1]):

LL:= L[1..-2]+L[2..-1]:

select(t -> member(LL[t], {2, 3, 5, 7, 11, 13, 17}), [$1..N]); # Robert Israel, May 20 2020

MATHEMATICA

ldQ[n_]:=Module[{ldn=Max[IntegerDigits[n]], ldn1=Max[IntegerDigits[ n+1]]}, PrimeQ[ldn+ldn1]]; Select[Range[150], ldQ]  (* Harvey P. Dale, Apr 29 2011 *)

PROG

(PARI) isok(m) = isprime(vecmax(digits(m))+vecmax(digits(m+1))); \\ Michel Marcus, May 20 2020

CROSSREFS

Cf. A054055.

Sequence in context: A028755 A187897 A187319 * A187899 A024609 A167056

Adjacent sequences:  A095973 A095974 A095975 * A095977 A095978 A095979

KEYWORD

base,easy,nonn

AUTHOR

Jason Earls, Jul 16 2004

STATUS

approved

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Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)