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A092403
a(n) = sigma(n) + sigma(n+1).
7
4, 7, 11, 13, 18, 20, 23, 28, 31, 30, 40, 42, 38, 48, 55, 49, 57, 59, 62, 74, 68, 60, 84, 91, 73, 82, 96, 86, 102, 104, 95, 111, 102, 102, 139, 129, 98, 116, 146, 132, 138, 140, 128, 162, 150, 120, 172, 181, 150, 165, 170, 152, 174, 192, 192, 200, 170, 150, 228, 230
OFFSET
1,1
COMMENTS
a(n) is the area of the terrace in the level 1 of the polycube called "tower" described in A221529 where the longest side of its base is equal to n + 1, thus a(n) has a symmetric representation. - Omar E. Pol, Jul 22 2021
FORMULA
a(n) = A346533(n+1,n). - Omar E. Pol, Jul 22 2021
MATHEMATICA
Total/@Partition[DivisorSigma[1, Range[70]], 2, 1] (* Harvey P. Dale, Feb 19 2018 *)
PROG
(PARI) for(i=1, 60, print1(", "sigma(i)+sigma(i+1)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon Perry, Mar 22 2004
STATUS
approved