A053237 Numbers n such that both A053230(n) and A053230(n+1) = 1.

1, 31, 38, 67, 74, 98, 128, 197, 228, 240, 247, 277, 283, 307, 313, 332, 339, 369, 382, 400, 413, 430, 459, 489, 502, 520, 551, 609, 622, 646, 664, 729, 759, 771, 823, 830, 843, 908, 915, 940, 969, 1038, 1057, 1086, 1117, 1124, 1148, 1206, 1247, 1266, 1290

Offset: 1

Author

Asher Auel, Jan 10 2000

Keywords

• nonn

Comments

Pairs of consecutive 1's occur uncommonly often in A053230.

Crossrefs

Cf. A000203, A053224, A053230, A053231, A053232, A053233, A053234, A053235, A053236.

Programs

Maple

with(numtheory): f := [seq( `if`((sigma(i+1) > sigma(i)),i,print( )), i=1..5000)];
seq(`if`((f[i+2]-f[i+1]=1) and (f[i+1]-f[i]=1),i,print( )), i=1..1500);