A219110 Numbers for which at least one sum of two adjacent digits is not prime.

10, 13, 15, 17, 18, 19, 22, 24, 26, 27, 28, 31, 33, 35, 36, 37, 39, 40, 42, 44, 45, 46, 48, 51, 53, 54, 55, 57, 59, 60, 62, 63, 64, 66, 68, 69, 71, 72, 73, 75, 77, 78, 79, 80, 81, 82, 84, 86, 87, 88, 90, 91, 93, 95, 96, 97, 99, 100, 101, 102, 103, 104, 105

Offset

1,1

Comments

Different from A104211 where ("only") the sum of all digits is considered; of course exactly the two-digit terms coincide.

Numbers missing in A182177 and A182178. Otherwise said, complement of the range of A182177 (in the set of nonnegative integers) and of the range of A182178 (in the set of positive integers) and of A182175 in the set of integers > 9.

Links

Table of n, a(n) for n=1..63.

M. F. Hasler in reply to E. Angelini, Re: Any digit-pair in S sums to a prime, SeqFan list, Apr 11 2013

Example

102 is here because 1+0 is not prime (even though 0+2 is).

Mathematica

Select[Range[10, 105], MemberQ[PrimeQ[Total /@ Partition[IntegerDigits[#], 2, 1]], False] &] (* T. D. Noe, Apr 16 2013 *)

Prog

(PARI) is(n)=for(i=2, #n=digits(n), isprime(n[i-1]+n[i])||return(1))

Crossrefs

Sequence in context: A061837 A256477 A247464 * A226024 A134651 A135548

Adjacent sequences: A219107 A219108 A219109 * A219111 A219112 A219113

Keyword

nonn,base,easy

Author

M. F. Hasler, Apr 11 2013

Status

approved