A336864 Bogotá numbers k such that k + 1 is also Bogotá number.

0, 24, 2510, 5210, 8991, 56384, 348732, 460719, 867839, 28997919, 193889375, 254181375, 419321664, 1018179999, 2654951424, 1297015971839, 62061633644031

Offset: 1

Author

Seiichi Manyama, Aug 06 2020

Keywords

• nonn
• more
• base

Comments

a(18) > 10^15 if it exists. - David A. Corneth, Aug 06 2020

From Chai Wah Wu, Aug 17 2020: (Start)

The following numbers are terms:

2805402158142975 = 153931531311*(1*5*3*9*3*1*5*3*1*3*1*1) = 111822471227*(1*1*1*8*2*2*4*7*1*2*2*7) - 1.

8748948067725824 = 2441112742111*(2*4*4*1*1*1*2*7*4*2*1*1*1) = 53339113353*(5*3*3*3*9*1*1*3*3*5*3) - 1.

(End)

Examples

			   n | a(n)                               a(n)+1
-----+------------------------------------------------------------------
   1 | 0 = 0 * 0                          1 = 1 * 1
   2 | 24 = 12 * (1*2)                    25 = 5 * 5
   3 | 2510 = 251 * (2*5*1)               2511 = 93 * (9*3)
   4 | 5210 = 521 * (5*2*1)               5211 = 193 * (1*9*3)
   5 | 8991 = 333 * (3*3*3)               8992 = 1124 * (1*1*2*4)
   6 | 56384 = 881 * (8*8*1)              56385 = 537 * (5*3*7)
   7 | 348732 = 3229 * (3*2*2*9)          348733 = 7117 * (7*1*1*7)
   8 | 460719 = 7313 * (7*3*1*3)          460720 = 11518 * (1*1*5*1*8)
   9 | 867839 = 17711 * (1*7*7*1*1)       867840 = 5424 * (5*4*2*4)
  10 | 28997919 = 119333 * (1*1*9*3*3*3)  28997920 = 51782 * (5*1*7*8*2)
		

Links

• Puzzling Stackexchange, Pairs of Bogotá numbers, 2020.

Crossrefs

Cf. A336826.

Extensions

a(11)-a(17) from David A. Corneth, Aug 06 2020