Original entry on oeis.org
10153331, 20326464, 30559685, 40871218, 51193539, 63296870, 75460003, 87623334, 99816467, 112128400, 124441719, 139544852, 154778073, 170089706, 185421637, 200754756, 216907889, 233061220, 249234353, 265565884, 281897715
Offset: 1
a(7) = 10153331 + 10173133 + 10233221 + 10311533 + 10322321 + 12103331 + 12163133 = 75460003 is prime. a(21) = 10153331 + 10173133 + 10233221 + 10311533 + 10322321 + 12103331 + 12163133 + 12163331 + 12193133 + 12311933 + 12313319 + 15103133 + 15233221 + 15311633 + 15331931 + 15333119 + 16153133 + 16153331 + 16173133 + 16331531 + 16331831.
A047841
Autobiographical numbers: Fixed under operator T (A047842): "Say what you see".
Original entry on oeis.org
22, 10213223, 10311233, 10313314, 10313315, 10313316, 10313317, 10313318, 10313319, 21322314, 21322315, 21322316, 21322317, 21322318, 21322319, 31123314, 31123315, 31123316, 31123317, 31123318, 31123319
Offset: 1
Ulrich Schimke (ulrschimke(AT)aol.com)
10313314 contains 1 0's, 3 1's, 3 3's and 1 4's, hence T(10313314) = 10313314 is in the sequence
The entry 3122331418, for instance, is a member since it is indeed made up of three 1's, two 2's, three 3's, one 4 and one 8.
- J. N. Kapur, Reflections of a Mathematician, Chapter 33, pp. 314-318, Arya Book Depot, New Delhi 1996.
- Abraham Verghese, Cutting for Stone: A Novel. New York: Alfred A. Knopf (2009): 294.
Cf.
A005151, which is the sequence 1, T(1), T(T(1)), .. ending in the fixed-point 21322314.
A109776
Self-describing numbers: reading the number gives a (possibly redundant) description of the number.
Original entry on oeis.org
22, 4444, 224444, 442244, 444422, 666666, 10123133, 10123331, 10143133, 10143331, 10153133, 10153331, 10163133, 10163331, 10173133, 10173331, 10183133, 10183331, 10193133, 10193331, 10212332, 10213223, 10232132
Offset: 1
"22" does indeed consist of "two 2's".
-
fQ[n_] := Block[{id = IntegerDigits[n]}, If[ OddQ[ Length[id]], Return[False], Union[Reverse@# & /@ Tally[id]] == Union@ Partition[id, 2]]]; k = 1; lst = {}; While[k < 10^7, If[fQ@ k, AppendTo[lst, k]; Print[k]]; k++]; lst (* Robert G. Wilson v, Apr 27 2012 *)
A173101
Self-describing semiprimes.
Original entry on oeis.org
22, 10183133, 10183331, 10213223, 10313317, 10322123, 10331831, 10331931, 10333117, 12183133, 12183331, 12193331, 12311033, 12311633, 12311833, 12313318, 12331031, 12333115, 12333119, 14103331, 14153331, 14163133, 14173133, 14183133, 14193331, 14311533, 14311633
Offset: 1
a(1) = 22 because "22" does indeed consist of "two 2's" and 22 = 2 * 11 is semiprime. a(4) = 10213223 because 10213223 consists of one "0", two 1's, three 2's, and two 3's; and 10213223 = 41 * 249103 is semiprime.
Showing 1-4 of 4 results.
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