A374101 - OEIS

A374101

Numbers k such that k and k+2 are both self numbers (A003052).

1, 3, 5, 7, 108, 209, 310, 411, 512, 613, 714, 815, 916, 1109, 1210, 1311, 1412, 1513, 1614, 1715, 1816, 1917, 2110, 2211, 2312, 2413, 2514, 2615, 2716, 2817, 2918, 3111, 3212, 3313, 3414, 3515, 3616, 3717, 3818, 3919, 4112, 4213, 4314, 4415, 4516, 4617, 4718

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OFFSET

1,2

COMMENTS

The least difference between consecutive self numbers is 2 (see Griffin N. Macris's proof at A010061 that may be adapted to other bases).

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

seq[max_] := Module[{c = Complement[Range[max], Table[n + DigitSum[n], {n, 1, max}]], d, ind}, d = Differences[c]; ind = Position[d, 2] // Flatten; c[[ind]]]; seq[5000]

CROSSREFS

Subsequence of A003052.

Cf. A010061, A339216 (binary analog).

Sequence in context: A110337 A132287 A046201 * A292848 A128344 A259385

Adjacent sequences: A374098 A374099 A374100 * A374102 A374103 A374104

KEYWORD

nonn,base,easy

AUTHOR

Amiram Eldar, Jun 28 2024

STATUS

approved