This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A128983 #3 Mar 30 2012 17:39:19 %S A128983 0,1,2,0,4,0,8,6,9,10,16,12,32,18,33,34,64,36,128,66,129,130,256,132, %T A128983 257,258,134,260,512,264,1024,514,1025,1026,268,1028,2048,1032,2049, %U A128983 2050,4096 %N A128983 Rightmost position of n in A089625, 0 if absent. %C A128983 Numbers n have A000586(n) decompositions into sums of distinct primes and occur A000586(n) times in A089625. The sequence is the rightmost (largest) index (position) of n in A089625. It is an inverse of A089625 made unique in the sense that in the prime decomposition of n the one with the largest primes are chosen and converted to binary. The sequence therefore is a binary representation of a greedy decomposition of n into a sum of primes. %F A128983 A089625(a(n))=n if n not equal to 1, 4 and 6. %e A128983 Prime decompositions of n=25 are 1*11+1*7+1*5+0*3+1*2 (binary tagged 11101=29) %e A128983 or 1*13+0*11+1*7+0*5+1*3+1*2 (binary 101011=43) or %e A128983 1*13+0*11+1*7+1*5+0*3+0*2 (binary 101100=44) or 1*17+0*13+0*11+0*7+1*5+1*3+0*2 %e A128983 (binary 1000110=70) or 1*23+0*19+0*17+0*13+0*11+0*7+0*5+0*3+1*2 (binary 100000001 %e A128983 =257). Out of these indices 29, 43, 44, 70 and 257, the largest is chosen, a(25)=257. %Y A128983 Cf. A089625, A000586. %K A128983 nonn %O A128983 1,3 %A A128983 _R. J. Mathar_, Apr 30 2007