# A152990: Sum of proper divisors minus the number of proper divisors of Fibonacci number A000045(n). # Table of n, a(n) for n = 1..80 # a(79-80) corrected by Georg Fischer, Feb 18 2020 with (Maple): # with(combinat): with(numtheory): seq(sigma(fibonacci(n))-fibonacci(n)-tau(fibonacci(n))+1, n = 1 .. 80); # _Emeric Deutsch_, Jan 02 2009 1 0 2 0 3 0 4 0 5 0 6 4 7 0 8 8 9 17 10 14 11 0 12 245 13 0 14 40 15 499 16 542 17 0 18 2801 19 148 20 5316 21 6771 22 286 23 0 24 110809 25 18032 26 752 27 124327 28 155934 29 0 30 1310617 31 2972 32 1213164 33 1821955 34 5166 35 2697336 36 33280689 37 506376 38 1416024 39 32030851 40 106878198 41 62156 42 295708841 43 0 44 274335236 45 1063567695 46 17287530 47 0 48 11990512753 49 684728064 50 4727729904 51 10201638387 52 11257501230 53 55946692 54 99131708601 55 30055411700 56 165819223468 57 203237589679 58 10053832114 59 2710261048 60 4549796958577 61 555008008 62 8957137512 63 4685115907951 64 5928096489222 65 3521953273876 66 25163549044649 67 167501530140 68 25779137874836 69 60353386851855 70 91498522595058 71 46165377744 72 1451980584573601 73 95396544 74 27354085383728 75 1881590310358967 76 1303840362406862 77 492122969280268 78 8164277999600409 79 92180471494908 80 25521744587250716