A225417 Composite numbers which contain their sum of aliquot parts as a substring.

6, 28, 121, 437, 496, 611, 1331, 1397, 8128, 10201, 14641, 27019, 40301, 40991, 41347, 41917, 45743, 47873, 49901, 51101, 67997, 76459, 97637, 99101, 99553, 99779, 120353, 133307, 133961, 134179, 153091, 161051, 165101, 165743, 166171, 182525, 186503

Offset

1,1

Comments

A(n) is odd deficient or perfect (A000396).

If definition had not excluded prime numbers, then terms of A208270 would have been included. - Michel Marcus, Dec 18 2013

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Example

1031311 is in the sequence because 1031311=10211*101, Sum of aliquot parts: 1+101+10211=10313, substring of 1031311.

Prog

(PARI) indigit(a, b)={ u=Vec(Str(a)); v=Vec(Str(b)); indi=0; la=#u; lb=#v; i=1; while(i<=la-lb+1&&indi==0, d=0; for(x=1, lb, if(v[x]==u[i+x-1], d+=1)); indi=(d==lb) ; i+=1); return(indi)}
{for(i=1, 10^7, k=sigma(i, 1)-i; if(indigit(i, k)&&isprime(i)==0, print(i)))}

Crossrefs

Sequence in context: A330532 A037131 A292485 * A026851 A267689 A300996

Adjacent sequences: A225414 A225415 A225416 * A225418 A225419 A225420

Keyword

nonn,base

Author

Antonio Roldán, May 07 2013

Status

approved