Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #7 Oct 27 2023 22:00:45
%S 1,31,38,67,74,98,128,197,228,240,247,277,283,307,313,332,339,369,382,
%T 400,413,430,459,489,502,520,551,609,622,646,664,729,759,771,823,830,
%U 843,908,915,940,969,1038,1057,1086,1117,1124,1148,1206,1247,1266,1290
%N Numbers n such that both A053230(n) and A053230(n+1) = 1.
%C Pairs of consecutive 1's occur uncommonly often in A053230.
%p with(numtheory): f := [seq( `if`((sigma(i+1) > sigma(i)),i,print( )), i=1..5000)];
%p seq(`if`((f[i+2]-f[i+1]=1) and (f[i+1]-f[i]=1),i,print( )), i=1..1500);
%Y Cf. A000203, A053224, A053230, A053231, A053232, A053233, A053234, A053235, A053236.
%K nonn
%O 1,2
%A _Asher Auel_, Jan 10 2000