A348302 Lexicographically earliest sequence of distinct terms such that the sum of two neighboring digits is not a palindrome.

1, 9, 3, 7, 5, 8, 2, 82, 84, 6, 4, 64, 66, 46, 48, 28, 49, 19, 37, 39, 55, 57, 58, 59, 67, 68, 69, 73, 75, 76, 77, 78, 79, 85, 86, 87, 88, 89, 91, 93, 94, 95, 96, 97, 98, 99, 191, 919, 193, 737, 373, 739, 194, 646, 464, 648, 282, 828, 284, 649, 195, 555, 557, 375, 558, 285, 559, 196, 466, 467, 376, 468, 286

Offset

1,2

Comments

The digit zero must be absent of the sequence.

Links

Table of n, a(n) for n=1..73.

Example

The 1st digit of the seq + the 2nd digit = (1 + 9) = 10 (not a palindrome);
the 2nd digit of the seq + the 3rd digit = (9 + 3) = 12 (not a palindrome);
the 3rd digit of the seq + the 4th digit = (3 + 7) = 10 (not a palindrome);
the 4th digit of the seq + the 5th digit = (7 + 5) = 12 (not a palindrome); etc.

Mathematica

q[n_] := n < 10 || !AnyTrue[Plus @@@ Partition[IntegerDigits[n], 2, 1], PalindromeQ]; a[1] = 1; a[n_] := a[n] = Module[{k = 2, t = Array[a, n - 1]}, While[!q[k] || MemberQ[t, k] || PalindromeQ[Mod[a[n - 1], 10] + First[IntegerDigits[k]]], k++]; k]; Array[a, 100] (* Amiram Eldar, Nov 28 2021 *)

Crossrefs

Cf. A236689.

Sequence in context: A136251 A073002 A357044 * A197836 A011282 A196823

Adjacent sequences: A348299 A348300 A348301 * A348303 A348304 A348305

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Nov 27 2021

Status

approved