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A070242
Card( k>0 : sigma(k)=sigma(n) ).
5
1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 3, 3, 2, 2, 1, 1, 3, 2, 1, 3, 3, 2, 3, 1, 2, 1, 5, 2, 1, 3, 2, 3, 1, 1, 3, 2, 3, 3, 4, 1, 3, 1, 5, 3, 2, 1, 1, 5, 2, 2, 4, 5, 4, 2, 3, 3, 6, 1, 4, 2, 1, 3, 5, 1, 2, 4, 5, 5, 1, 1, 2, 2, 2, 4, 6, 2, 2, 1, 2, 3, 3, 2, 2, 4, 4, 3, 3, 1, 6, 2, 5, 4, 6, 2, 1, 2, 1, 1, 5, 2, 2, 5
OFFSET
1,6
LINKS
FORMULA
a(n) = A054973(A000203(n)). - Antti Karttunen, Nov 07 2017
PROG
(PARI) for(n=1, 150, print1(sum(i=1, 10*n, if(sigma(n)-sigma(i), 0, 1)), ", "))
(PARI) A070242(n) = { my(s=sigma(n)); length(select(i->sigma(i) == s, vector(s, i, i))); } \\ Antti Karttunen, Nov 07 2017
(PARI) A070242(n) = { my(s=sigma(n)); sum(k=1, s, (sigma(k)==s)); }; \\ Antti Karttunen, Nov 07 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 09 2002
STATUS
approved