A157107 Indices of 4's in A090822.

220, 440, 661, 881, 1105, 1325, 1546, 1766, 1991, 2211, 2432, 2652, 2876, 3096, 3317, 3537, 3771, 3991, 4212, 4432, 4656, 4876, 5097, 5317, 5542, 5762, 5983, 6203, 6427, 6647, 6868, 7088, 7326, 7546, 7767, 7987, 8211, 8431, 8652, 8872, 9097, 9317, 9538

Offset: 1

Author

Paul Curtz, Feb 23 2009

Keywords

• nonn

Comments

Despite appearances, this is a highly irregular sequence. - N. J. A. Sloane

The first pair of consecutive 4's occurs at position 255895648634818208370064452304769558261700170817472823398081\

655524438021806620809813295008281436789493636145 [Gijswijt, 2016, page 12]. - Sergio Pimentel, Feb 21 2017

Comment from N. J. A. Sloane, Feb 28 2017: (Start)

Page 12 of Gijswijt (2016) states:

"In dat stuk vinden we 355 promoties en daarmee 355 stukken lijm van lengte 1, 3, 1, 9, 4, 24, 1, 3, ... Na 355 keer verdubbelen en lijm toevoegen vinden we uiteindelijk de eerste dubbele vier in A090822, en wel op positie

255.895.648.634.818.208.370.064.452.304.769.558.

261.700.170.817.472.823.398.081.655.524.438.021.

806.620.809.813.295.008.281.436.789.493.636.145".

A rough translation might be:

"... we find 355 promotions and thus 355 glue segments of lengths 1, 3, 1, 9, 4, 24, 1, 3, ...

We eventually find the first pair of consecutive 4's in A090822 at position

255,895,648,634,818,208,370,064,452,304,769,558,

261,700,170,817,472,823,398,081,655,524,438,021,

806,620,809,813,295,008,281,436,789,493,636,145."

Dion Gijswijt, Mar 01 2017 adds that the number mentioned is the position of the second 4 in the first occurrence of 4,4 in A090822. For the glue segments see A091579.

(End)

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..300
• Dion Gijswijt, Krulgetallen, Pythagoras, 55ste Jaargang, Nummer 3, Jan 2016.

Crossrefs

Cf. A090822, A091579.

Extensions

Edited by N. J. A. Sloane, Feb 24 2009

More terms from R. J. Mathar, Feb 24 2009